ENGLISH 01-2019

Edition 01/2019

Index
Pag.
subject index ii
how does the diffusive sampler work? A1
why is radiello so special? A3
the components of radiello A5
the adsorbing cartridge A5
the diffusive body A5
the supporting plate A5
the label A5
how to use radiello A6
before sampling: assembling the supporting plate A6
on-field: to start the sampling A6
after the sampling A7
radiello maintenance A7
radiello-ready-to-use A8
accessories for radiello B1
vertical adapter B1
shelter B1
how to assemble the shelter B2
on-field temperature measurements B3
calibration solution for H2S B4
filtration kit B4
calibration solutions for aldehydes B4
calibration solutions for BTEX (CS2 desorption) B5
calibration solutions for VOCs in workplace environments B5
calibration solutions for BTEX (thermal desorption) B6
the spare parts of radiello B6
empty cartridge B6
barcode adhesive label B6
clip B6
tube B6
strip B6
aldheydes C1
volatile organic compounds (VOCs) chemically desorbed with CS2 D1
volatile organic compounds (VOCs) thermally desorbed E1
nitrogen and sulfur dioxides (NO2 and SO2) F1
ozone (O3) G1
hydrogen sulfide (H2S) H1
ammonia (NH3) I1
hydrochloric acid (HCl) J1
hydrofluoric acid (HF) K1
anaesthetic gases and vapours L1
phenol, methylphenol and dimethylphenol (thermally desorbed) M1
1,3-butadiene & isoprene N1
index by code Z1

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Subject index

acetaldehyde, B4, C1 1,4-dichlorobenzene, D2, E3, E5, E6

acetone, D2, D6 1,2-dichloroethane, D2
acetonitrile, D2 dichloromethane, D2, D6
acrylonitrile, D2 1,2-dichloropropane, D2, D6
acrolein, B4, C1, C3 diethyl ether, D2
activated charcoal, A2, A3, B5, D1, D6, E1, L1 diffusive body - blue, A5, A8, C1, F1, G1, H1, I1, K1, J1
activated charcoal, duration and storage, D4, L2 diffusive body: section, A1
adsorbing surface, A1 diffusive body - white, A5, A8, D1, E2, H1, I1, K1, J1, M1
adsorption isotherm, E1 diffusive body - yellow, A5, A8, E1, E2
aldehydes, B4, C1 diffusive surface, A1, A2, A3
aldehydes, analyses, C3 dimethyl disulfide, E3
aldehydes, duration and storage, C2 N,N-dimethylformamide, D2
aldehydes, exposure, C2 N,N-dimethyl-p-phenylendiammonium, H1
aldehydes, interferences, C4 2,3-dimethylphenol, M1
aldehydes, sampling rates, C1 2,5-dimethylphenol, M1
ammonia, A8, I1 2,6-dimethylphenol, M1
amyl acetate, D2 3,5-dimethylphenol, M1
anaesthetic gases and vapors, L1 3,5-dimethylphenol, M1
axial diffusion, A1, A2 2,4-dinitrophenylhydrazine, C1, C3
back diffusion, A3, E1 1,4-dioxane, D2
barcode label, A5, A6, B6 1,2-di(4-pyridyl)ethylene, G1
barcode label, instruction, A6 n-dodecane, D2
benzaldehyde, B4, C1 empty cartridge, B6
benzene, A3, B5, B6, D2, D4, D5, E3, E4, E5 end caps for glass tubes, B6
benzyl alcohol, D2 ethanol, D2
breakthrough, A3 ethyl acetate, D2, D6
bromochloromethane, D2 ethylbenzene, B5, B6, D2, D5, E3, E4
BTEX, desorbed with CS2, D5 ethyl-tert-butyl ether (ETBE), D2
BTEX, thermally desorbed, E4 2-ethyl-1-hexanol, D2
1,3-butadiene, N1 2-etoxyethanol, D2, D6
butanal, B4, C1 2-etoxyiethyl acetate, D2
butanol, D2 1-etoxy-2-propanol, D6
sec-butanol, D2 ethrane, L1
ter-butanol, D2 ferric chloride, H1
2-butoxyethanol, D2, D6, E3 filtration kit, B4, C1, G1
2-butoxyethyl acetate, D2 florisil, C1
butyl acetate, D2, D6, E3 formaldehyde, B4, C1
calibration, kit for BTEX thermally desorbed, B6 Freundlich, isotherm of -, E1
calibration, kit for BTEX with CS2, B5 glass tube, B6
calibration, kit for COVs workplace environments, B5 glutaric aldehyde, C1
calibration, solution for H2S, B4 graphitised charcoal, A2, E1
carbon tetrachloride, D2 graphitised charcoal, duration and storage, E3
clip, A5, B6 graphitised charcoal, recovery, E6
chlorobenzene, D2 halothane, L1
chloroform, D2 n-heptane, D2, D6, E3
components of radiello, A5 hexanal, B4, C1
COVs (see volatile organic compounds) n-hexane, D2, D6, E3
m-chresol (2-methylphenol), M1 1-hexanol, D2
o-chresol (3-methylphenol), M1 hydrochloridric acid, A8, J1
p-chresol (4-methylphenol), M1 hydrofluoric acid, A8, K1
cyanoferrate, I1 hydrogen sulfide, A8, H1
cyclohexane, D2, D6, E3 indophenol, I1
cyclohexanol, D2, D6 isobutanol, D2, D6
cyclohexanone, D2, D6 isobutyl acetate, D2, D6
n-decane, D2, D6, E3 isoflurane, L1
desorption with CS2, D1 isooctane, D2, D6
diacetone alcohol, D2, D6 isopentanal, B4, C1, C3

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isoprene, N1 sterilization, L2
isopropanol, D2, D6 styrene, D2, D6, E3
isopropyl acetate, D2, D6, E3 sulphanilammide, F2
isopropylbenzene, D2 shelter, B1, B2
limonene, D2, E3 silica gel, G1, J1
maintenance of radiello, A7 strip for shelter B2, B6
MBTH, G1 sulfur dioxide, A8, F1
MBTH-azide, G1 supporting plate, A5
methanol, D2, D6 Tenax TA, M1
2-methoxyethanol, D2, E3 tetrachloroethylene, D2, D6, E3
2-methoxyethyl acetate, D2, E3 tetrahydrofuran, D2
1-methoxy-2-propanol, D2, D6, E3 thermal desorption, E1
1-methoxy-2-propyl acetate, D2, D6 thermal desorption, calibration, E5, M4
methyl acetate, D2, D6 thermal desorption, cartridge recovery, E6
3-methyl-2-benzothiazolinone hydrazone (v. MBTH) thermometer, B3
methyl-tert-buthylether (MTBE), D2 thermometer, reader, B3
methylcyclohexane, D2, D6 thermometer, software, B3
methylcyclopentane, D2 toluene, B5, B6, D2, D5, E3, E4
methylene blue, H1 1,1,1-trichloroethane, D2, D6, E3
methylethylketone, D2 trichloroethylene, D2, D6
methylisobuthylketone, D2, D6 triethanolamine, F1
methyl metacrylate, D2 1,2,4-trimethylbenzene, D2, D6, E3
2-methylpentane, D2, D6 n-undecane, D2, D6, E3
3-methylpentane, D2, D6 using radiello, A6
molecolar sieve, L1 vertical adapter, B1
molecolar sieve, duration and storage, L2 volatile organic compounds, thermal desorption, E1
naphtalene, D2 volatile organic compounds, thermal desorption, analyses, E4
NEDA, F2 volatile organic compounds, thermal desorption,
nitrogen dioxide, A8, F1 sampling rates, E1, E3
nitrous oxide, L1 volatile organic compounds, extraction with CS2, D1
n-nonane, D2, D6, E3 volatile organic compounds, extraction with CS2,
n-octane, D2, D6, E3 analyses, D4
ozone, A8, C4, G1 volatile organic compounds, extraction with CS2,
ozonide, G1 sampling rates, D1, D2
ozonolysis, G1 volatile organic compounds, extraction with CS2,
pentacyanonitrosylferrate (see cyanoferrate) retention times GC, D6
pentane, D2, D6 m-xylene, B5, B6, D2, D5, E3, E4
pentanal, B4, C1 o-xylene, B5, B6, D2, D5, E3, E4
permeative body, A5, L1 p-xylene, B5, B6, D2, D5, E3, E4
phenol, I1, M1 xylenol (see dimethylphenol)
a-pinene, D2, D6, E3
polycarbonate screw-thread cap for radiello-ready-to-use, A8
polypropylene tube, B6
propanal, B4, C1
propyl acetate, D2, D6
propylbenzene, D2
4-pyridylaldehyde, G1
radial diffusion, A1, A2
reader for on-field thermometer, B3
ready-to-use, radiello -, A8
sampling, ending, A7
sampling, preparing, A6
sampling, sampling rate, definition, A1
sampling, to start on-field, A6
sevorane, L1
snapping adapter, A8
sodium hypochlorite, I1

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how does
t h e d i ff u s i v e s a m p l e r w o r k ?
The diffusive sampler is a closed box, usually cylindrical. Of its two opposite sides,
one is “transparent” to gaseous molecules which cross it, and are adsorbed onto
the second side. The former side is named diffusive surface, the latter is the adsor-
bing surface (marked with S and A in the figure). axis
Driven by the concentration gradient dC/dl, the gaseous molecules cross S and
diffuse towards A along the path l, parallel to the axis of the cylindrical box. The
molecules, which can be trapped by the adsorbing material, are eventually adsor-
bed onto A according to the equation: diffusive surface S l
dm dC
=DS [1]
adsorbing surface A
dt dl In the diffusive sampler, the adsor-
where dm is the adsorbed mass during time dt and D is the diffusion coefficient. bing and the diffusive surfaces are
Let C be the concentration at the diffusive surface and C0 the concentration at two opposing plane of a closed box.
Driven by the concentration gra-
the adsorbing surface, the integral of [1] becomes
dient, the gaseus molecules (colou-
m S (C-C ) red in the figure) pass through the
=D [2]
t l 0
diffusive surface and are trapped
from the adsorbing surface.
If the concentration at the adsorbing surface is negligible, the equation can be
approximated to
m S m
= D = Q and then C = [3]
tC l tQ
Q is the sampling rate and has the dimensions of a gaseous flow (if m is expressed in µg, t in minutes and C in
µg·l-1, Q is expressed in l·min-1).
Therefore, if Q is constant and measured, to calculate the ambient air concentration you need only to quantify the mass of
analyte trapped by the adsorbing material and to keep note of the time of exposure of the diffusive sampler.
To improve the analytical sensitivity the collected mass m should be increased by enlarging Q. As D is a
constant term, one can only try to improve the S/l ratio, namely the geometrical constant of the sampler.
Unfortunately, in the common axial simmetry sampler, if S is enlarged, the adsorbing surface A must be
enlarged too, in order to keep the two parallel surfaces at a fixed distance. Since the analytes can be reco-
vered from the axial sampler only by solvent extraction, any increase of A lead to a proportional increase
of the extraction solvent volume, thus the improvement of Q is canceled out by the effect of dilution.
The value of distance l could also be reduced, but under
the critical value of about 8 mm the diffusion law is no
longer valid in the case of low air velocity values, since diffusive

adsorption rate becomes higher than supplying rate of

surface adsorbing

analyte molecules at the diffusive surface.

surface

Cannot we improve Q then?

The answer is to improve the sampler geometry to a radial design. Section of radiel-
radiel-
lo Diffusive and
lo.
From this idea the radiello sampler has been developed, its cylindrical adsorbing surfa-
outer surface acting as diffusive membrane: the gaseus molecules move ces are cylindrical
axially parallel towards an adsorbent bed which is cylindrical too and and coaxial: a
coaxial to the diffusive surface. large diffusive sur-
When compared to the axial sampler, radiello shows a much higher dif- face faces, at a
fixed distance, the
fusive surface without increase of the adsorbing material amount. Even if
small surface of a
the adsorbing surface is quite smaller then the diffusive one, each point of little concentric
the diffusive layer faces the diffusion barrier at the same distance. ra cartridge.
rd

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As S=2prh (where h is the height of the cylinder) and the diffusive path is as long as the radius r, we can then
express equation [1] as follows
dm dC
= D 2p h r [4]
dt dr
The integral of equation [4] from rd (radius of the diffusive cylindrical surface) to ra (radius of the adsorbing surface)
becomes
m 2p h
=D r =Q [5]
tC
ln d
ra

the ratio
2p h
r
ln d
ra

is the geometrical constant of radiello.

radiello The calculated uptake rate [5] is
The microporous sin- therefore proportional to the height of the diffusive cylinder and inversely
tered polyethylene
proportional to the logarithm of the ratio of diffusive vs adsorbing cylin-
diffusive barrier of
der radii.
radiello photogra-
phed at the electron
While ra can be easily measured, rd can only be calculated by exposure
microscope; the path
length is much longer
experiments. Actually the diffusive membrane has been designed with a
than the membrane thick tubular microporous layer. The actual diffusive path length is the-
thickness due to the tortuosity of the pores. refore much longer than the distance among the diffusive and adsorbing
surfaces due to the tortuosity of the path through the pores. A diffusive
cylinder of external diameter 8 mm, thickness 1.7 mm and average poro-
sity of 25 µm, coupled to an adsorbing cartridge with radius 2.9 mm
creates a diffusive path of 18 mm instead of the straight line path esti-
mation of (8-2.9) = 5.1 mm.
The sampling rate Q is function of diffusive coefficient D, which is a thermodynamic property of each chemical sub-
stance. D varies with temperature (T) and pressure (p); therefore also the sampling rate is a function of those varia-
bles according to
Q = f (T, p)
Q values that will be quoted in the following have been measured at 25 °C and 1013 hPa. As a consequence, they
should be corrected so as to reflect the actual sampling conditions.
The correction of Q for atmospheric pressure is usually negligible since its dependence is linear and very seldom
we face variations of more than 30 hPa about the average value of 1013 hPa. In the worst case, if corrections for
pressure are ignored you make an error of ±3%, usually it is within ±1.5%.
On the other hand, Q depends exponentially on temperature variations, therefore more relevant errors can be intro-
duced if average temperature is significantly different from 25 °C. Moreover, when chemiadsorbing cartridge are
used kinetic effects (variations of reaction velocities between analyte and chemiadsorbing substrate) can be evident,
apart from thermodynamic ones (variation of D).

It is therefore very important to know the average temperature in order to ensure accuracy of experimental
data. See how you can perform on-field temperature measurements on page B3.

Even if some cartridges adsorb large quantities of water when exposed for a long time in wet atmosphere, gene-
rally this does not affect sampling by radiello.
radiello Some consequences, neverthless, can sometimes be felt on the
analysis. As an example, a very wet graphitised charcoal cartridge could generate ice plugs during cryogenic focu-
sing of thermally desorbed compounds or blow out a FID flame.
It is therefore important to protect radiello from bad weather. See page B1 how this can be easily done.

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why is radiello so
sp ecial?
The diffusive sampling does not involve the use of heavy and encumbering pumping systems, does not have energy
power supply problems, does not require supervision, is noiseless, is not flammable and does not represent an
explosion hazard, can be performed by everybody everywhere and with very low costs.
Moreover, it is not subject to the breakthrough problem, which can be serious when active pumping is performed.
In pumped sampling the adsorbed compound beha-
ves as a chromatographic peak (top): air flow displa-
ces it along the adsorbent bed and its concentration
is distributed as a gaussian function. Eventually, the
compound comes out from the opposite end. When
its concentration in the outlet air is 10% of the con-
centration in the sampled air we say that the
breakthrough has been reached or, with a mislea-
ding expression, that the tube has been saturated.
Any further pumping leads to a loss of analyte and a
-3
100 µg.m
consequent underestimation of the environmental
100
pumpled
concentration. The extent of this phenomenon
µg.m-3 flowing out
samplers
depends weakly on the concentration of target com-
80

pound but rather on the value of air flow, the overall

sampling volume and the chemical compound invol-
60 -3
50 µg.m
ved. 40
In the graph the case of benzene is displayed, sam-
pled at 25 °C onto an activated charcoal adsorbent 20

bed of the same volume of a code 130 radiello car-

-3
10 µg.m

tridge. The breakthrough is reached after 35, 44 or 0

49 liters of sampled air depending on benzene con-

1000 2000 3000 4000

centration in air (10, 50 or 100 µg·m-3 respectively).

35 49 1600 2300 3050
44 back-diffusion
air (litres)

An apparently similar phenomenon is shown by

radiello also. In this case, however, we cannot
speak of breakthrough, since no actual air flow is involved, but rather of backdiffusion. This consists of a decrease of the
value of m·Q-1·t-1 (which is equal to the measured concentration, see eqn. [3] on page A1). This term is constant and equal to
the actual concentration until the adsorbed mass of analyte is far from the maximum amount allowed by the adsorbing medium
capacity. The extent of backdiffusion depends on concentration and exposure time but a decrease of 10% in the m·Q-1·t-1
term is observed along with equivalent sampling volumes of magnitude bigger than those seen before: 1600, 2300 and 3050
liters at the concentration of 10, 50 and 100 µg·m-3.

Why diffusive sampling has not been so extensively adop-

ted up to now?
This is due to the fact that the traditional axial symmetry
sampler has generally poor sensitivity and reproducibility
because of the limits set by its geometry. On one side,
uptake rate values are generally low, on the other, they
often vary depending on environmental conditions.
These limitations have been overcome by radiello.
radiello
By virtue of radial simmetry, uptake rate is:
For a traditional
P high, since it does not vary linearly axial simmetry
but exponentially with the ratio diffusi- sampler the
ve surface vs diffusive path length uptake rate
(see eqn. [5]). With the same dimen- increases linearly with tha ratio of diffusive surface vs diffusive path length, while
sions, radiello’s uptake rate is at least for the radial simmetry sampler, the corresponding increase is exponential. This
three times higher than that of any means that, let the diffusive surface vs diffusive path length ratio be 8:1, for the
axial diffusive sampler; axial sampler the uptake rate value is 8 (regardless of dimensions) while for the
radial one it is 45.

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Edition 01/2019

P constant, due to the great adsorbing capacity of the

adsorbing substrates;
P reproducible, for the continuous control of the
homogeneity of the materials used and of all the pro-
duction lots of radiello;
P precisely measured, because the flow rate is not
estimated but calculated experimentally, measured
in dynamic atmosphere controlled chamber in a
wide range of conditions of concentration, tempera-
ture, humidity, air velocity, presence of interfering

Moreover, radiello
4is able to work properly also with bad weather conditions
due to the water-repellent diffusive body
4has blank values lower than three times the instrumental
noise due to the complex conditioning procedures of the
bulk adsorbing (or chemiadsorbing) materials and to the
repeated quality controls along the whole production
4has low detection limits and high adsorbing capacities that
allow exposure time duration from 15 minutes to 30 days
and concentration measurements from 1 ppb to over 1000
ppm
4offers high precision and accuracy over a wide range of
exposure values

4 allows thermal desorption and HRGC-MS

analysis without interferents
4 is suited to the sampling of a vast range of
gaseous pollutants
4 is though and chemically inert, being made of
polycarbonate, microporous polyethylene and
stainless steel
4 is indefinitely reusable in all of its components
apart from the adsorbing cartridge; the latter
can be recovered if thermal desorption is
employed
4 it comes from the efforts of one of the main
European scientific research institutions that
produces it directly by high technology equip-
ment and continuously submits it to severe
tests and performs research and development
in its laboratory in Padova

All the images in the manual concern the Environmental Research Center of the Istituti Clinici Scientifici Maugeri

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t h e c o m p o n e n ts o f
radiello
The essential parts of radiello are the adsorbing cartridge, the diffusive body, the supporting plate and the adhesi-
ve label with the bar code indication. Apart from the adsorbing cartridge, if not differently stated, all of the other
components can be repeatedly used for several sampling
The ads or bing c ar t ri dge experiments.
Depending on the polluting compound to be
sampled, many different adsorbing or chemiad- T h e d i f f u s i v e b o d y
sorbing cartridges have been developed. Their Four kinds of diffusive bodies are available, with like outer dimen-
dimensions are neverthless the same for all: 60 sions: 60 mm height and 16 mm diameter.
mm length and 4.8 or 5.8 mm diameter. The white diffusive body, code RAD120, of general use, is made
They are contained in glass or plastic tubes of microporous polyethylene 1.7 mm thick and average porosity
wrapped up in a transparent polyethylene ther- 25 ± 5 µm. Diffusive path length is 18 mm.
mowelded bag. The blue diffusive body, code RAD1201, has the same proper-
The code number, printed onto the bag along ties of the white one but is opaque to light: it is suited to the sam-
with the lot number and expiry date indicates the pling of light-sensitive compounds.
kind of cartridge. The yellow diffusive body, code RAD1202, should be used whe-
Apart from the thermal desorption cartridges, all never the sampling rate must be reduced; it is made of micropo-
of the other kinds are for single use only. rous polyethylene 5 mm thick and average porosity 10 ± 2 µm.
Available in 5 or 20 pieces per package. Diffusive path length is 150 mm.
The cartridge has to be introduced into the The permeative diffusive body, code RAD1203, is a 50 µm thick
diffusive body. silicone membrane strengthened by a stainless steel net and a
microporous polyethylene cylinder. It is employed for anaesthetic
gases and vapours sampling.
Available in 20 pieces per package only.
The diffusive body has to be screwed onto the supporting plate.

T h e su p p o r ti n g p l a t e
It is identified by the code 121.
Made of polycarbonate, it acts
both as closure and support for RAD120 RAD1201 RAD1202 RAD1203
the diffusive body, which has
to be screwed onto the The lab el
thread. It comes along with a Self-adhesive, with printed bar-
clip and a transparent code number. Since each bar-
adhesive pocket to hold code number has been printed
the label. The three in only one copy, it allows an
parts are to be assem- unmistakable identification of
bled before use (see the sampling tube on field and
page A6). in the laboratory for the subse-
Available in 20 quent analysis.
pieces per pac- Each package of 20 adsorbing
kage only. cartridges contains also 21 labels.
code RAD190 If the labels are ordered separately,
code RAD121 they are shipped in 198 pieces per
package only.

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Edition 01/2019

how to use radiello as se mbling th e

b efo re sa mplin g s up po rting p late

Before using radiello, you have to assemble the supporting plate with the clip, necessary to suspend it, and the
adhesive label pocket.
insert the clip strip in the ply the strip and insert the peg into
1 2
slot, with the peg facing the hole
upwards

peel off the

3 transparent
pocket

user tip
assemble the supporting
plate in your laboratory
before the sampling cam-
paign: on the field they are
uselessly time-consuming.
and stick it onto the plate in a central position; 4
if you prefer, the pocket can be applied to the rear of the plate, but
BE CAREFUL, always with the label insertion slot on the side
(otherwise, if it starts raining the label can get wet)
o n-field
to start the sam pling
1
open the plastic bag, draw the cartridge out from the tube and put
it in the diffusive body. Keep the glass or the plastic tube and
stopper in the original plastic bag.
The lower part of the diffusive body holds a seat for the
central positioning of the cartridge. A correctly centered
cartridge should not stick out even by half a millime-
ter. If it is not so, the cartridge is not cor-
rectly positioned and is out of axis.
As a consequence, when the diffusive body is
screwed onto the supporting plate the cartridge is
bent, the geometry of the sampler is disturbed and 2 keeping the diffusive
the results obtained become unreliable. body in a vertical posi-
To place the cartridge centrally you need tion, screw it onto the
only to tap on the supporting plate.
diffusive body.
BE CAREFUL: do not hold
user tip the diffusive body hori-
Do not touch the zontally when you screw
cartridge with your it onto the plate, otherwise the cartridge could
fingers if possible, come out from its seat and stick out.
particularly if it is Insert a label in the pocket without peeling it
impregnated with 3 off. Keep note of the date and time and expo-
reactive se radiello. Sampling has started.

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user tip
even if you can write date and time of the sampling start and end on the adhesive label, we suggest you to keep
note of these parameters also separately: after a week exposure with bad weather conditions, your writings could
become illegible!
DO NOT USE MARKING PENS to write on the label: they contain solvents that are sampled by radiello!

after th e sa mpling
Keep note of the date and time of the end of exposure.
4
Place the cartridge into the tube, peel off the label and stick it onto the
tube such that the barcode is parallel to the axis of the tube.
If you have performed the sampling of different polluting compounds at the same
time, BE CAREFUL NOT TO MIX UP THE TUBES: place the exposed cartridge in
its original tube, identified by the code printed on the plastic bag.

IMPORTANT
Always stick the label such that the barcode is parallel to the axis of the tube:
any other position will compromise the barcode automated reading by the optic
reading device.

maintenance
When exposed outdoors or in a workplace environment, the diffusive body may get dirty from airborne dust. Fine
particles (PM10) are especially harmful to yellow diffusive bodies since they can obstruct the pores. When the diffu-
sive bodies are dirty you can wash them as follows.
Immerse the diffusive bodies in a beaker with a soapy solution (e.g. dish detergent) and sonicate them for 20 minu-
tes. As the diffusive bodies float, you may make them sink by putting a smaller beaker on them, with water inside
enough to dip it a few centimeters.
Rinse the diffusive bodies with plenty of water and then deionized water; let them finally dry in the air.

IMPORTANT: NEVER USE SOLVENTS TO

CLEAN THE DIFFUSIVE BODIES!!!

After four or five washings, diffusive bodies need replacing: repeatedly adsorbed dust may have penetrated the
pores such deeply to be undisturbed by washing.
The following table shows the advised washing schedule:

PM10 concentration (µg·m-3) <30 40 >50

Washing after days of exposure 45 30 15

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radiello - r e a d y - t o - u s e
The ready-to-use version may be advantageous when you prefer not to assemble all of the components on field. It
can be purchased as it is or in separate parts to be assembled by the customer.
In the as-it-is version the adsorbing cartridge is already contained in a diffusive body closed with a poly-
carbonate screw-thread cap. The whole is closed in a polypropylene airtight container. Just before use
draw the diffusive body out of the container and fit it to the special snapping vertical adapter fixed to the
supporting plate. After the end of exposure, the diffusive body with its content is placed again in the poly-
propylene airtight container to be shipped to the laboratory for analysis. The ready-to-use as-
it-is radiello (polycarbonate cap, glass or plastic tube, special vertical adapter, barcode label
and polypropylene container comprised for each type) is available for the sampling of the fol-
lowing compounds:

code sampling of contains

RAD1231 BTEX and VOCs white diffusive body and cartridge code RAD130
RAD1232 BTEX and VOCs yellow diffusive body and cartridge code RAD145
RAD1233 NO2, SO2 and HF blue diffusive body and cartridge code RAD166
RAD1233 Aldehydes blue diffusive body and cartridge code RAD165
RAD1235 ozone blue diffusive body and cartridge code RAD172
RAD1236 hydrogen sulfide white diffusive body and cartridge code RAD170
RAD1237 ammonia blue diffusive body and cartridge code RAD168 on top:
to the right, radiello-ready-to-use
RAD1238 HCl white diffusive body and cartridge code RAD169 to the left, the diffusive body with the
polycarbonate cap and the adsorbing
cartridge inside
IMPORTANT: in the ready-to-use version in the center: the special snapping
the supporting plate is not provided. adapter
near here: the supporting plate with
If you prefer to assemble it by yourselves, you should order: the vertical snapping adapter

ü diffusive bodies (of the required type, see following chapters) user tip
ü adsorbing cartridges (of the required type, see following chapters)
ü polycarbonate caps, code RAD1241 the ready-to-use version of radiello
ü special snapping adapters, code RAD1221 is very useful in the workplace sam-
ü polypropylene containers, code RAD1242 pling campaigns but is not advised if
ü supporting plates, code RAD121 very low concentrations in outdoor or
domestic environments are to be
measured

Fit the diffusive body to the Draw the diffusive body by

adapter by pushing it till tilting it with decision
you hear a clicking sound

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accessories
vertical adapter
code RAD122
Available in 20 pieces per package only
The diffusive body can be fitted to the supporting plate either in a vertical or
horizontal position, the vertical one being more comfortable when radiello is
used for personal sampling.
To assemble radiello in vertical position you have
to screw it to the vertical adapter code RAD122,
fitted to the supporting plate.

code RAD122

place the vertical adapter over the moun-

1
ting point on the plate
press the adapter onto the plate with your thumbs till
2
the ridge fits the edge of the plate.

The adapter can be

removed from the plate
by lifting the ridge

IMPORTANT
when mounting the diffusive body be careful to
keep it vertical with the thread upside (see
page A6).

shelter
code RAD196
For outdoor exposures a mountable polypropylene shelter is available
which can be hanged to lamp posts.
Available in 10 pieces per package only
It has been designed to be mounted easily and without any tool on
field, so that it is not cumbersome when you transport it from your labo-
ratory. Once assembled, it ensures the best compromise between pro-
tection against bad weather and ventilation.
It can house up to four radiello and is able to fit a wide range of pole
diameters.
Its colour is quite similar to that of the majority of lampposts: being less
visible, it is less subject to acts of vandalism.

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Edition 01/2019

Il riparo è formato da:

h ow t o as se m ble t he sh elt e r
All of the components are snap-on One of the three equi-
assembled. valent panels will act
as the roof of the
shelter
(quotes are in mm)
First of all, insert on this panel (the
roof) the two supports that will be
used to suspend the samplers.

the two supports

where to suspend
radiello

two spacers

two strips

Then fix the two walls on

the sides of the roof panel.

The whole becomes rigid by

insertion of the two spacers.
Fit them to the slots on
bottom of the side panels
and turn them by 90°
(performing this rotation you
may feel some resistance,
but go on until you hear a
clicking sound).

Finally, insert two plastic strips in the rear vertical

slots of the side panels. The strips are also availa-
ble as spare parts, in 100 pieces per package,
identified by the code RAD198.
Suspend the shelter to the pole by closure of the strips, but DO NOT
DRAW SO MUCH THAT THE SHELTER IS DEFORMED. If the pole has
diameter larger than 20 cm, the shelter leans on the curved edges on the rear of the sidewalls. If the pole has a
smaller diameter, it leans against the curved edge of the roof panel and the rear spacer. If the diameter of the pole
is very small the shelter bows down, the wind may make it go round, or the shelter may even slip down to ground.
It is then advisable to choose another pole.

user tip
If the pole diameter is larger than the strip length, you can put two or more strips together to extend the fastening
system.
If the sampling site is very windy, do not introduce more than two radiello samplers in each shelter, otherwise rain
could dampen the outermost samplers.

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O n - f i e l d t e m p e r a t u r e m e a s u r e m e n ts
codes RAD126 and RAD127
Since the uptake rate values of radiello depend on tempera-
ture, the concentration values obtained will be more accurate
if precise temperature measurements are performed during
the sampling.
To get reliable temperature data you may ask the local weather
station, if there is one, and if the measurements are performed
nearby your sampling sites. Bear in mind that you should take
into the account the urban heat island: did you know that there
can be a difference of even 4-5 °C between the center and the
suburbs of a big town?
With radiello you can create your own temperature
measurement station.

A thermometer with precision ± 0,5 °C between -20 and 80 °C thermometer code RAD126
and equipped with a data logger capable of recording 2048 data points Available in 3 pieces per package only
has been fixed to a vertical adapter (code RAD126). It is tiny enough (<
1 cm3) to go perfectly unobserved.
It has no battery to replace, needs no maintenance and works properly even with bad weather conditions.
Its memory allows you to record one temperature value every 15
minutes for 22 days, or every 30 minutes for 43 days, or every 60
minutes for 85 days, or... it lasts ten years or a million readings!
The thermometer is fitted to the supporting plate of radiello: use
the sampler normally and measure temperature and pollution at
the same time.
A very simple reader (code RAD127), connected to your PC by
a serial port, allows you to program the temperature sensor for
the measurements on field, to download the aquired data and to
perform data statistical and graphic processing by a very user-
friendly software.
One reader serves an unlimited number of thermometers. The reader code RAD127
SmartButton Reader Solution software needed to program the ther- single unit, serial port adapter included
mometers and download the data can be purchased from the
parent company's website at the link:
http://www.acrsystems.com

user tip
When performing urban monitoring install a thermometer every
ten sampling sites. IIf this may help you, contact us to discuss
sampling strategies.

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c a l i b r a t i o n s o l u t i o n f o r H 2S
code RAD171
Code RAD171 relieves you from the task of preparing the sodium sulfide standard solution for the calibration curve
used for the determination of H2S by the cartridge code 170 (see page H1).
Since sodium sulfide is deliquescent, its weight is not a primary standard and sodium sulfide solution need titration
once prepared. Moreover, titration must be repeated often due to the instability of diluted solution (one hour time is
sufficient to decrease sulfide content by 10%).
Code RAD171 is a methylene blue concentrated solution
that, once diluted 1:50, provides the same absorbance equivalent to
Solution ml of ml of water
value at 665 nm of a sodium sulfide solution of with con- µg.ml-1 of S=
centration 1.145 µg·ml-1 sulfide ions. A 2 di codice 171 98 1.145
This concentration value has been chosen to obtain the
B 25 di A 25 0.572
highest absorbance value within the linearity range of the
spectrophotometer. C 10 di A 40 0.229

To obtain a complete calibration curve, just dilute the D 5 di A 45 0.115

mother solution as shown in the table.
Code RAD171 allows you to prepare as many as 50 calibration curves.
Kept closed at room temperature, code RAD171 solution is stable for at least one year.

filtration kit
code RAD174
Code RAD174 filtration kit is composed by 20 single use plastic syrin-
ges and 20 single use micropore hydrophilic polypropylene filters with
diameter 13 mm and 0.45 µm porosity.
Both filter and syringe are suited to filtration of aqueous solutions with
pH in the range of 0 to 12 with commonplace eluents for ion chromato-
graphy and reverse phase HPLC.

calibration solutions for aldehydes

code RAD302 2,4-DNPH of µg·ml-1 as aldehyde
Calibration curves for aldehydes are obtained with standard solu-
tions of the corresponding 2,4-dinitrophenylhydrazones (see page formaldehyde 50
C1). Although their synthesis is straightforward, their purification is acetaldehyde 50
tricky and time-consuming. Code RAD302 offers a certified and
convenient choice: a solution of nine 2,4-dinitrophenylhydrazones acrolein 10
in a solvent compatible with HPLC eluents and with concentrations
propanal 50
suitable for the preparation of calibration curves in the range
usually spanned by radiello samples. butanal 50
Code RAD302 is delivered as 10 ml of acetonitrile solutions of the
isopentanal 50
nine 2,4-dinitrophenylhydrazones formed by the aldehydes listed
in the table, contained in a pierceable-septum crimped cap vial. pentanal 50
The listed concentration values are indicative, actual ones are cer-
tified for each lot. hexanal 50
Kept tightly capped in a dark place at 4 °C, the solution is stable benzaldehyde 50
for at least four months.

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calibration solutions for BTEX

(CS2 desorption)
code RAD405
Code RAD405 calibration kit has been conceived for the analy-
sis of BTEX sampled in urban environments by the cartridge
code RAD130 and chemically desorbed by carbon disulfide
(see page D1).
The kit may be used both for routine calibration and for sche-
duled quality control of the calibration procedure described on
page D4.
It is composed of 12 code RAD130 cartridges, three of which
code simulated concentrations in µg·m-3 are blanks and nine, divided into three groups of three, preloa-
RAD405 (7 days exposure equivalent) ded with BTEX to simulate 7 days exposures (10,080 minutes)
to the concentrations listed in the table. The values shown are
Group 1 Group 2 Group 3
indicative, actual ones are certified for each lot.
benzene 1 10 50
The mass of each analyte deposited onto the cartridge spans
toluene 2 20 100 the whole range of concentrations usually found in urban envi-
ronments, extreme values included.
ethylbenzene 1 10 50
BTEX loading is performed by injection of precisely known
m-xylene 1 10 50 amounts of vaporized standard solutions in CS2 of the five
p-xylene 1 10 50 compounds under nitrogen flow.
Kept at 4 °C, the cartridges are stable for at least four months.
o-xylene 1 10 50

calibration solutions for VOCs

in workplace environments
code simulated concentrations in mg·m-3
code RAD406 RAD406 (8 hours exposure equivalent)
The code RAD406 kit has been conceived for scheduled
Group 1 Group 2 Group 3
quality control of the calibration procedure for the analysis
of volatile organic compounds (VOCs) sampled by code benzene 0.1 0.2 0.4
RAD130 cartridges in workplace environments (see page
D4).
toluene 19 38 76

It is composed of 12 code RAD130 cartridges, three of ethylbenzene 12 24 48

which are blanks and nine, divided into three groups of m-xylene 12 24 48
three, preloaded with VOCs to simulate 8 hours exposures
(480 minutes) to the concentrations listed in the table. The p-xylene 12 24 48

values shown are indicative, actual ones are certified for o-xylene 12 24 48
each lot.
The composition of the mixture is simple but it includes butanol 15 30 60

compounds with different polarity. The loaded mass is cal- 2-etoxyiethyl acetate 2.5 5 10
culated in order to represent exposures to 0.5, 1 and 2
times the TLV value for the mixture.
VOCs loading is performed by injection of precisely known amounts of calibrated mixtures of the eight compounds
under nitrogen flow.
Kept at 4 °C, the cartridges are stable for at least four months.

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calibration solutions for BTEX

(thermal desorption)
code simulated concentrations in µg·m-3
RAD407 (7 days exposure equivalent)

Group 1 Group 2 Group 3 code RAD407

benzene 1 5 25
Code RAD407 calibration kit has been conceived for the analysis
of BTEX sampled in urban environments by the cartridge code
toluene 2 10 50 RAD145 and thermally desorbed (see VOCs - thermal desorp-
ethylbenzene 1 5 25
tion).
The kit may be used both for routine calibration and for scheduled
m-xylene 1 5 25
quality control of the calibration procedure described on page E5.It
p-xylene 1 5 25 is composed of 12 code RAD145 cartridges, three of which are
blanks and nine, divided into three groups of three, preloaded with
o-xylene 1 5 25
BTEX to simulate 7 days exposures (10,080 minutes) to the con-
centrations listed in the table.
The values shown are indicative, actual ones are certified for each lot.
BTEX loading is performed by injection of precisely known amounts of vaporized standard solutions in methanol of
the five compounds under nitrogen flow. During the analysis the chromatographic peak of methanol will be visible.
Kept at 4 °C, the cartridges are stable for at least four months.

the spare parts Barcode

adhesive
Empty cartridge label
Can be loaded by the customer with the desi- Codice RAD190
red adsorbent. Available in 198 pieces
It is delivered with the two end caps and the per package only
glass tube.
Available in 20 pieces per package only.

codice RAD175
stainless steel net, Clips
100 mesh, 5.9 mm Code RAD195
Available in 20 pieces
per package only.
codice RAD176
stainless steel net,
100 mesh,
4.9 mm diameter
codice RAD177 Tubes
stainless steel net, Available in 20 pieces per package only.
3x8 µm,
4.9 mm diameter
code RAD1991
glass tube,
working volume 2.8
Strip ml
Code RAD198
Useful for repositioning of
radiello shelter. code RAD1992
Lenght 75 cm. polypropylene tube,
Available in 100 pieces working volume
per package only. 12 ml

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Aldehydes
what you need
blue diffusive body code RAD1201
supporting plate code RAD121
vertical adapter code RAD122 (optional)
chemiadsorbing cartridge code RAD165
filtration kit code RAD174 (only for analysis)

Principle
Code 165 is a stainless steel net cartridge filled with 2,4-dinitrophenylhydrazine (2,4-DNPH) coated Florisil®.
Aldehydes react with 2,4-DNPH to give the corresponding 2,4-dinitrophenylhydrazones
O2N R O2N R
F-NH-NH2 + O=C F-NH-NH=C + H 2O
O2N H O2N H
2,4-DNPH aldehyde 2,4-DNPhydrazone

The 2,4-dinitrophenylhydrazones are then extracted with acetronitrile and analyzed by reverse phase HPLC and UV
detection.

Sampling rates
Sampling rates values at 298 K (25 °C) and 1013 hPa are listed below:

sampling rate linearity range limit of quantitation1 uncertainty at 2s

ml·min-1 µg·m-3·min µg·m-3 %
acetaldehyde 84 1,000÷12,000,000 0.1 15.9
acrolein 33 3,000÷3,000,000 0.3 16.5
benzaldehyde 92 1,000÷8,000,000 0.1 17.2
butanal 11 9,000÷10,000,000 0.9 23.5
hexanal 18 5,000÷15,000,000 0.6 20.2
formaldehyde 99 1,000÷4,000,000 0.1 13.8
glutaric aldehyde 90 1,000÷3,000,000 0.1 14.5
isopentanal 61 1,500÷12,000,000 0.2 17.0
pentanal 27 4,000÷12,000,000 0.4 22.9
propanal 39 3,000÷8,000,000 0.3 17.1
1
after 7 days exposure
Effect of temperature, humidity and wind speed
Sampling rate varies from the value at 298 K on the effect of temperature (in Kelvin) as expressed by the following
equation:

QK = Q298 ( 298
K
) 0.35

where QK is the sampling rate at the temperature K and Q298 is the reference value at 298 K. This produces a varia-
tion of ± 1% for 10 °C variation (upwards or downwards) from 25 °C.
Sampling rate is invariant with humidity in the range 15-90% and with wind speed between 0.1 and 10 m·s-1.

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Calculations
The average concentration C over the whole sampling time (in µg·m-3) is calculated according to the expression:
m [µg]
C [µg·m-3] = 1,000,000
Q [ml·min-1] · t [min]
where:
m = mass of aldehyde in µg
t = exposure time in minutes

Exposure
The optimum exposure duration varies with the expected concentration. Taking formaldehyde as an example, con-
centration values of 5-30 µg·m-3 are usually found in outdoor urban measurements while 20-200 µg·m-3 are expec-
ted in workplace environments. In workplace environments concentrations may be as high as 2,000-3,000 µg·m-3
for short time intervals: it can therefore be interesting to evaluate the peak value (usually referred to by STEL). The
corresponding advised exposure time is shown in the table below:
Advised exposure times

outdoor indoor workplace environment

environment environment average conc. peak conc.
Formaldehyde stability in the cartridge

minimum 8h 8h 2h 15 minutes
30,0
µg found onto the cartridge

maximum 7 days 7 days 8h

25,0 1h

20,0

Do not expose all of the cartridges belonging to the same lot: keep at least two cartridges as blanks.
15,0

Storage 10,0

The cartridges need to be kept, properly sealed, in a dark place at 4 °C for ensuring a shelf life (according to EN
0 1 3 5 7 14 21 28 35 42 60

13528-2) of six months. If stored at -18 °C, the shelf life will be twelve months. Each lot is approved for use when
days after exposure

the blank value of formaldehyde and acetaldehyde are

less than 0.1 µg and 0.3 µg per cartridge, respectively,
corresponding to a concentration in air less than 0.1
and 0.25 µg·m-3 over one week of exposure, respecti-
vely. The blank value may increase with time.
After exposure keep the cartridges well capped at 4 °C,

Formaldehyde stability in solution

28.0
26.0
24.0
22.0
µg found

20.0
18.0
16.0

Formaldehyde stability in the cartridge after the sampling (on

14.0

top) and in solution (left). The stability tests were performed

12.0

upon cartridges exposed for one week in a standard atmo-

10.0
8.0
0 1 2 4 6 14 21 28 35 42 sphere chamber at 25 °C and with 50% relative humidity and at
two different concentration levels. Each bar in the plot repre-
sents the average and error from the analysis of six samples.
days after desorption

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they are stable for 60 days. After solvent desorption (see Analysis) discard the cartridge. The resulting solution, well
capped and stored at 4 °C, is stable for at least 42 days.

Analysis
Desorption
Materials user tip
- HPLC grade acetonitrile
For a reliable and rapid filtra-
- class A volumetric pipette, capacity 2 ml
tion employ the filtration kit
- micropore filter membranes, porosity 0.45 µm, solvent resistant
code RAD174.
Procedure
To obtain an accurate calibra-
Introduce 2 ml acetonitrile directly in the cartridge tube, recap and stir from time
tion curve we offer you the cali-
to time for 30 minutes. Discard the cartridge. Filter the resulting solution and keep
bration solution code RAD302.
it well capped until analysis time. If analysis has to be delayed, store the solution
at 4 °C.

Instrumental analysis
The method suggested below is only indicative; the analyst can choo- IMPORTANT: verify the presence
se an alternative method, on the basis of its personal experience. and the abundance of the 2,4-DNPH
chromatographic peak: otherwise, the
cartridge could be saturated.
Materials
- reverse phase C18 HPLC column, length
formaldehyde

acetaldehyde

150 mm, 4.6 mm diameter, 5 µm packing

particle size
2,4-DNPH

- HPLC apparatus capable of elution

gradient and UV detection

benzaldehyde
isopentanal
Procedure
Set the detector at the wavelength of 365 pentanall
nm. Inject between 10 and 50 µl of solu-
hexanal
acrolein

propanal

tion and elute as follow:

- flow: 1.9 ml·min-1
butanal

- Isocratic elution with acetonitrile/water

38:62 v/v for 10 minutes, up to acetoni-
trile/water 75:25 v/v in 10 minutes,
reverse gradient to acetonitrile/water
38:62 v/v in 5 minutes.
On the right: the chromatogram of a real
sample analyzed under the described
conditions.
HPLC chromatogram of aldehydes sampled by radiello

IMPORTANT
Acrolein gives place to three chromatographic peaks, two of them are unresolved. Calculate the concentration
basing onto this most abundant peak and ignore the others.
Isopentanal appears as two unresolved peaks: its concentration should be obtained by integration of both peaks
as a sum.

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user tip
If you perform several analyses, a barcode reader will greatly improve productivity in your laboratory and will also
minimize the possibility of errors in the copying of sample labels.
Please contact us to help you in the implementation of the reader.

Interferences
Other carbonyl compounds
All carbonyl compounds, ketones included, react with 2,4-DNPH but do not interfere in the analysis if proper
chromatographic parameters are selected.
In the described chromatographic conditions acetone-2,4-DNPH peak is well resolved from acrolein-2,4-DNPH.
Neverthless, if acetone concentration is higher than 50,000 µg·m-3, acrolein-2,4-DNPH peak intensity is depressed
by 25%.

Ozone
Examples of ozonolysis of dinitrophenylhydrazones on Effetto dell'ozono sulla portata
active supporting materials as silica gel are found in the
literature.
105

On code 165 cartridge, packed with coated Florisil®, ozo-

100

nolysis is much less important than on any other com-

formaldeide
portata normalizzata

95
acetaldeide

mercial aldehyde sampling device, either diffusive or

90
acroleina

pumped, and becomes appreciable only if ozone con-

85 propanale

centration, averaged over the whole exposure time inter-

80 benzaldeide

val, is higher than 100 ppb. Since this is not usually the
isopentanale
75
pentanale

case, generally no correction is needed to take into

70
esanale

account ozone concentration. If there is firm evidence

65

that ozone concentration is equal or higher than 100 ppb

60

over the whole exposure time, make use of the corrected

0 50 100 150

sampling rate values shown in the table below, where

O3 ppb

[O3] is ozone concentration in ppb. Portata di campionamento in funzione della concentrazione di

The listed values are referred to the temperature of 298 ozono, posta uguale a 100 quella misurata a concentrazione zero
K (25 °C), for deviations larger than ± 10 °C substitute di ozono. Con l’eccezione dell’acetaldeide, l’effetto dell’ozono
diventa sensibile solo a concentrazione superiore a 100 ppb, inte-
the base value (e.g. 99 ml·min-1 for formaldehyde) with
sa come valore medio dell’intero periodo di esposizione.
the corrected value calculated according to equation on
page C1.
No experimental data is available for butanal and glutaric aldehyde.

corrected sampling rate

ml·min-1
acetaldehyde 84-0.018[O3]* Sampling rate
acrolein 33-0.027[O3] for ozone con-
centration [O3]
benzaldehyde 92-0.05[O3]
in ppb (apply
hexanal 18-0.02[O3] only if [O3]
formaldehyde 99-0.02[O3] >100 ppb)
isopentanal 61-0.06[O3]
pentanal 27-0.01[O3]
propanal 39-0.03[O3]

*applicare per concentrazioni di ozono pari o superiori a 50 ppb

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Volatile organic compounds (VOCs)

chemically desorbed with CS2

what you need

white diffusive body code RAD120
supporting plate code RAD121
vertical adapter code RAD122 (optional)
chemiadsorbing cartridge code RAD130
Or: radiello-ready-to-use code RAD1231

Principle
Code RAD130 cartridge is a stainless steel net cylinder, with 100 mesh grid opening and 5.8 mm diameter, packed
with 530 ± 30 mg of activated charcoal, particle size is 35-50 mesh. Volatile organic compounds are trapped by
adsorption and recovered by carbon disulfide displacementI, analysis is performed by FID gas chromatography.

Sampling rates
The table on pages D2 and D3 lists sampling rate values at 298 K (25 °C) and 1013 hPa, experimentally measured
in a standard atmosphere chamber. For other compounds whose diffusion coefficient1 is known sampling rate can
be calculated according to equation [5] on page working principle, taking into account that white diffusive body and
code 130 cartridge give the geometric constant of radiello the value of 14.145 ± 0.110 cm. Several experiments per-
formed in the standard atmosphere chamber demonstrate that the calculated sampling rates seldom deviate by
more than ±10% from the experimentally measured values.

Effect of temperature, humidity and wind speed

Sampling rates varies from the value at 298 K on the effect of temperature (in Kelvin) as expressed by the following
equation:

QK = Q298 ( 298
K
) 1,5

where QK is the sampling rate at the temperature K and Q298 is the reference value at 298 K. This produces a varia-
tion of ±5% for 10 °C variation (upwards or downwards) from 25 °C.
Sampling rate is invariant with humidity in the range 15 ÷ 90% and with wind speed between 0.1 and 10 m·s-1.
1
Lugg G.A.: Diffusion Coefficients of Some Organic and Other Vapors in Air. Anal. Chem. 40-7:1072-1077 (1968).

Calculations
The listed sampling rate values already take into account for the desorption efficiency with carbon disulfide. The ave-
rage concentration over the exposure time interval is therefore calculated from the mass of analyte found onto the
cartridge and exposure time without introducing any corrective factor, apart from corrections due to average tem-
perature different from 25 °C.
Average concentration (in µg·m-3) over the whole exposure time is calculated according to the following expression:
m [µg]
C [µg·m ] = -3
1,000,000
QK [ml·min-1] · t [min]
where:
m = mass of analyte in µg
t = exposure time in minutes

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Sampling rate values at 25°C (298 K)

sampling rate linearity range uncertainty at 2s notes

ml·min-1 µg·m-3·min %
acetone 77 10,000-600·106 7.0 a
acetonitrile 73 10,000-6·106 8.2 b
acrylonitrile 75 1,000-50·106 2.2
benzyl alcohol 37 1,000-800·106 6.5
amyl acetate 52 1,000-800·106 3.4
benzene 80 500-500·106 1.8
bromochloromethane 70 50,000-1,000·106 1.4
butanol 74 1,000-500·106 5.0
sec-butanol 64 1,000-300·106 5.2
tert-butanol 62 1,000-300·106 5.5
butyl acetate 60 1,000-1,000·106 3.0
2-butoxyethanol 56 1,000-100·106 5.7
2-butoxyethyl acetate 41 1,000-100·106 5.5
carbon tetrachloride 67 100,000-60·106 9.0
cyclohexane 54 500-500·106 4.5
cyclohexanone 68 5,000-120·106 4.2
cyclohexanol 54 5,000-120·106 4.5
chlorobenzene 68 1,000-1,000·106 3.6
chloroform 75 100,000-60·106 9.7 a
n-decane 43 500-1,000·106 1.1
diaceton alcohol 43 500-1,000·106 4.5
1,4-dichlorobenzene 51 1,000-1,000·106 7.7
1,2-dichloroethane 77 1,000-500·106 8.2
1,2-dichloropropane 66 500-250·106 4.5
dichloromethane 90 500-60·106 8.7
N,N-dimetylformamide 82 1,000-200·106 14.5 c
1,4-dioxane 68 1,000-600·106 5.5
n-dodecane 8 1,000-1,000·106 4.7
n-heptane 58 5,000-1,500·106 3.0
n-hexane 66 1,000-1,000·106 2.5
1-hexanol 52 5,000-120·106 5.5
ethanol 102 10,000-500·106 7.5 a-b
diethyl ether 78 5,000-500·106 12.0 a
ethyl acetate 78 1,000-1,000·106 1.5
ethylbenzene 68 1,000-1,000·106 2.4
2-ethyl-1-hexanol 43 5,000-500·106 10.1
2-ethoxyethanol 55 500-50·106 6.7 b
2-ethoxyethyl acetate 54 10,000-100·106 2.5
ethyl-tert-butyl ether (ETBE) 61 500-200·106 3.0
isobutanol 77 1,000-300·106 2.5
isobutyl acetate 63 1,000-1,000·106 5.2
isooctane 55 500-1,000·106 3.2
isopropanol 52 10,000-400·106 12.0 b
isopropyl acetate 66 1,000-1,000·106 9.9
isopropylbenzene 58 1,000-1,000·106 2.7
limonene 43 1,000-1,000·106 10.0
methanol 125 10,000-250·106 9.2 a-b
methyl acetate 80 1,000-1,000·106 12.0
methyl-ter-butyl ether (MTBE) 65 500-200·106 2.5

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sampling rate linearity range uncertainty at 2s notes

ml·min-1 µg·m-3·min %
methylcyclohexane 66 1,000-1,000·106 6.5
methylcyclopentane 70 1,000-1,000·106 2.5
methylethylketone 79 1,000-500·106 1.6
methylisobutylketone 67 1,000-250·106 8.7
methyl metacrylate 68 1,000-500·106 2.5
2-methylpentane 70 1,000-1,000·106 2.5
3-methylpentane 70 1,000-1,000·106 2.5
2-methoxyethanol 35 5,000-100·106 11.0 b
2-methoxyethyl acetate 56 2,000-100·106 3.0
1-methoxy-2-propanol 55 1,000-350·106 6.0
1-methoxy-2-propyl acetate 60 2,000-350·106 6.2
naphtalene 25 1,000-1,000·106 7.0
n-nonane 48 1,000-1,000·106 5.4
n-octane 53 500-1,000·106 3.2
pentane 74 1,000-1,000·106 1.9
a-pinene 53 1,000-1,000·106 7.0
propyl acetate 65 500-1,000·106 7.5
propylbenzene 57 1,000-1,000·106 2.9
styrene 61 1,000-500·106 3.0
tetrachloroethylene 59 10,000-500·106 2.5
tetrahydrofuran 74 2,000-250·106 11.0 b
toluene 74 500-1,000·106 1.5
1,1,1-trichloroethane 62 5,000-1,000·106 5.5
trichloroethylene 69 5,000-1,000·106 2.4
1,2,4-trimethylbenzene 50 500-1,000·106 6.6
n-undecane 24 1,000-1,000·106 10.0
m-xylene 70 500-1,000·106 2.5
o-xylene 65 500-1,000·106 2.5
p-xylene 70 500-1,000·106 2.5

Notes:
a = weakly adsorbed compound. If its concentration is higher than the TLV for the workplace environments it may be partially
displaced by other compounds that are more strongly trapped if their concentration is also high. If this is the case, it is advi-
sable to reduce sampling time under 8 hours.
b = prolonged exposure of charcoal cartridges at relative average humidity higher than 80% causes adsorption of up to 100 mg
of water. Water does not interfere with adsorption mechanisms but is displaced by carbon disulfide and gives raise to a sepa-
rate layer. Some very water soluble polar compounds will distribute between the two solvents, thus provoking an undere-
stimation of the actual air concentration since only the carbon disulfide is injected in the gas chromatograph. When the con-
centration of polar compounds has to be determined, the calibration curve should be prepared by spiking 50 µl of water in
each tube containing the cartridge and the 2 ml of carbon disulfide standard solution (see Analysis).
c = better reproducibility obtained by use of methanol as extraction solvent instead of carbon disulfide.

Limit of quantitation
The limit of quantitation depends on the instrumentation and on the analytical conditions. The minimum revealable
environmental concentration can be estimated on the basis of the equation on chapter Calculations, where m is the
minimum revealable mass, experimentally measured for each compound. Under the analytical conditions described
on the following chapter Analysis, the limit of quantitation for 7 days exposure usually ranges from 0.05 and 1 µg·m-3,
depending on the compound.
In any case, the limit of quantitation can never be lower than the inferior limit of the linearity range indicated in the
previous table.

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Edition 01/2019

Exposure
Code RAD130 cartridge has a very large loading capacity: about 80 mg, corresponding to an overall VOCs con-
centration of 3,000 - 3,500 mg·m-3 sampled for 8 hours or 70,000 - 80,000 µg·m-3 sampled for 14 days. Neverthless,
if the quantified overall adsorbed mass should be near 80 mg, sampling rate could have deviated from linearity. If
this is the case, it is advisable to repeat the sampling experiment reducing exposure time.

Workplace environment
In workplace environments complex mixtures of airborne solvent vapours are often found at concentrations 2,000-
3,000 mg·m-3. The outstanding adsorbing capacity of code RAD130 cartridges allows you to sample them for the
whole working shift of 8 hours. On the other hand, the very high values of sampling rates for a variety of compounds
allow you to perform accurate concentration measurements even after very short exposures. For example, 15 minu-
tes are enough to measure 0.1 mg·m-3 of benzene.
radiello can therefore be employed to evaluate both TWA and STEL concentrations.

Other indoor sampling experiments and outdoor campaigns

High sampling rates of radiello ensure very low limits of detection also for short exposure time intervals. For exam-
ple, you may measure benzene concentrations as low as 2 µg·m-3 with an error not exceeding 4% after 8 hours of
exposure. If radiello is exposed for 7 days, limit of quantitation becomes 0.1 µg·m-3.
Generally speaking, we suggest exposure time duration ranging from 8 hours to 30 days, the ideal value being 7
days.

Storage
The activated charcoal cartridges have undergone a complex conditioning process that ensures an outstanding
chromatographic blank level, never exceeding three times the instrumental noise of a FID detector at the lowest atte-
nuation.
Kept in a cool place and away from volatile organic compounds, the cartridges mantain unchanging blank level and
adsorbing capacity for at least two years. Expiry day and lot number are printed onto the plastic bag wrapping each
cartridge: its integrity stands as warranty seal.
After exposure the cartridges, well capped and kept in a cool and solvent-free place, maintain their content unalte-
rated for at least six months

Analysis
Extraction
Introduce 2 ml of CS2 and 100 µl of internal standard solution (see next) directly in the radiello glass tube without
drawing out the cartridge. Always use class A volumetric pipettes or dispensers. Stir from time to time for 30 minu-
tes. If analysis is not performed soon after, draw out the cartridge and
discard it. IMPORTANT
always use high purity grade CS2, for
example Honeywell cod. 342270.
Calibration
outdoor environment sampling BE CAREFUL
If benzene, toluene, ethylbenzene and xylenes (BTEX) have to be even refrigerated, CS2 permeates the
analyzed, prepare three or four standard solutions in CS2 having tube plastic cap: its volume decreases by
decreasing concentrations of the analytes in the following ranges (in 4-5% a day. If the internal standard has
mg·l-1): been added, it is only matter of unplea-
benzene 0.04 ÷ 17.6 etilbenzene 0.04 ÷ 17.7 sant odour...
toluene 0.09 ÷ 34.8 m-xilene 0.04 ÷ 17.2
o-xilene 0.04 ÷ 17.6 p-xilene 0.04 ÷ 17.2

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 Edition 01/2019

user tip
Analysis of unknown samples For a very accurate calibration
Identify the sample that has been exposed for the longest time or at the highest we offer the preloaded cartrid-
expected concentration. Introduce 2 ml of CS2 but do not add the internal stan- ges code 405 (outdoor envi-
dard, stir and let the sample stand for 30 minutes. Without discarding the cartrid- ronment) and code 406 (work-
ge, inject the CS2 solution in the gas chromatograph with FID detector (see place environment).
below), identify the compounds appearing in the chromatogram and make an esti-
mation of the order of magnitude of their concentrations.
Prepare a CS2 solution of the identified compounds with doubled concentration with respect to the sample. Dilute this
solution in order to obtain standard solutions of concentration respectively about 0.1, 0.5 and 1 times the concentra-
tion estimated in the sample. Introduce 2 ml of each standard solution onto a blank code RAD130 cartridge in its glass
tube, along with the chosen internal standard solution.
The chosen internal standard should have a retention time that does not cause interference with other compounds in
the chromatogram. Compatibly with this requirements, we suggest to employ a solution of 2-fluorotoluene (e.g. Aldrich
F 1,532-3) in CS2 with concentration of 100 µl·l-1 for outdoor samples and 2 ml·l-1 for workplace samples.
Add 2 ml of CS2 and the internal standard to all of the samples, stir, let the samples stand for 30 minutes and discard
the cartridges prior to the analysis.

Instrumental analysis (advised)

Capillary gas chromatography with FID detection
outdoor environment samples: 100% dimethylpolysi-
loxane column 0.2 mm·50 m, film thickness 0.5 µm; split
injection of 2 µl; split ratio 25:1; nitrogen carrier gas at
constant pressure of 20 psi; injector temperature 240
°C; oven initial temperature 35 °C for 5 minutes, 5
°C·min-1 up to 90 °C, maintain for 3 minutes, 10 °C·min-1
up to 220 °C, final isotherm for 5 minutes.
workplace samples: 100% dimethylpolysiloxane
column 0.2 mm·50 m, film 0.5 µm; split injection of 3 µl,
split ratio 100:1; carrier N2 at constant pressure of 20
psi; injector temperature 240 °C; oven initial temperatu-
re 50 °C for 5 minutes, 5 °C·min-1 up to 80 °C, 15
°C·min-1 up to 135 °C, 20 °C·min-1 up to 220 °C, final
isotherm 10 minutes. Total time: 29 minutes.
The retention times for several compounds analyzed
under the described conditions are listed in the table on On top: FID chromatogram of a real workplace sample
next page.
on the left: chromatogram of a real urban outdoor sample

USER TIP
If you perform several analyses, a barcode reader will
greatly improve productivity in your laboratory and will
also minimize the possibility of errors in the copying of
sample labels.
Please contact us to help you in the implementation of the
reader.

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Edition 01/2019

Perchè la cartuccia codice 130 non ha eguali?

retention the container

time
(minutes) The container is realised by stainless steel cloth AISI 316 with 100 mesh
methanol 4.834 opening. It is electric welded with no supply of foreign materials. It has tole-
ethanol 5.340 rance of ±0.05 mm diameter and of ±0.1 mm length.
acetone 5.712
isopropanol 5.835
pentane
methyl acetate
6.121
6.346
the contents
dichloromethane 6.405 The cartridge is packed with
2-methylpentane 7.559 vegetal activated charcoal with
methylethylketone 7.719
3-methylpentane 7.941 a very large adsorbing surface.
ethyl acetate 8.331 Its exceptionally low blank is
n-hexane 8.402 obtained by conditioning it in a
isobutanol 8.763 nitrogen stream fluidised bed
methylcyclopentane 9.350
1,1,1-trichloroethane 9.636 at 450 °C for 16 hours.
butanol 9.956 The fluidised bed technique
isopropyl acetate 9.978
does not only guarantee the
benzene 10.203
1-methoxy-2-propanol 10.424 thorough purification of adsor-
cyclohexane 10.580 bing material but also performs
1,2-dichloropropane 11.285 an accurate selection of its granulometry, by ventilation separations of the
trichloroethylene 11.625
fraction under 50 mesh and over 35 mesh.
isooctane 11.667
2-ethoxyethanol 11.831

the production
propyl acetate 11.868
n-eptane 12.068
1-ethoxy-2-propanol 12.775 The cartridge is filled up with charcoal by a very complex automated appara-
methylcyclohexane 12.912
methylisobutylketone 13.258
tus that was designed and realised in our laboratory. It avoids any contamina-
isobutyl acetate 14.005 tion of the adsorbing material during the delicate process of cartridge produc-
toluene 14.055 tion and ensures a very accurate dosing of the material itself, providing a varia-
butyl acetate 15.279 bility of less than 2% of the weight of the activated charcoal among the car-
n-octane 15.435
tetrachloroethylene 15.601
tridges.
diaceton alcohol 15.915

the quality controls

1-methoxy-2-propyl acetate 16.609
ethylbenzene 16.997
m+p-xylene 17.241
Each cartridge batch undergoes statistical quality control of the blank level.
cyclohexanone 17.436
cyclohexanol 17.436 If amounts higher than 20 ng of each of the BTEX compounds are found, the
styrene 17.716 entire lot is discarded.
o-xylene 17.832
2-buthoxyethanol 17.880
n-nonane 18.186 sampling rate measurements
a-pinene 19.129
n-decane 20.334 The sampling rate is measured in a standard atmosphere chamber unique
n-undecane 22.142 in Italy and one of the few found all over Europe.
It allows the dynamic generation of high flows of controlled concentration
gas mixtures from 1 µg·m-3 to 1,000 mg·m-3 (dynamic range from 1 to 106)
of each investigated compound alone or mixed with others. The chamber allows temperature control from -20 to 60
°C, relative humidity control from 5% to 100% and air speed variation from 0.1 to 10 m·s-1.
All of the gas flows are measured as mass flows and have therefore the properties of primary standards. All of the
operating parameters (gas flows, temperature, relative humidity, ...) are recorded and the records are available
along with the certification documents.

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 Edition 01/2019

Volatile organic compounds (VOCs)

thermally desorbed
what you need
yellow diffusive body code RAD1202
supporting plate code RAD121
vertical adapter code RAD122 (optional)
chemiadsorbing cartridge code RAD145

Principle
Code RAD145 is a stainless steel net cylinder, with 3x8 µm mesh opening and 4.8 mm diameter, packed with 350
± 10 mg of graphitised charcoal (Carbograph 4), particle size is 35-50 mesh.
Volatile organic compounds are trapped by adsorption and recovered by thermal desorption, analysis is performed
by capillary gas chromatography and FID or MS detection.

General considerations
Thermal desorption is an easy-to-use technique,
but it implies some precautions and is of less
k3>k2

general use than chemical desorption. k 2>k 1

The recovery of adsorbed compounds is based 100
°C
onto the different shape of adsorption isotherms
adsorbed mass (x/m)

25 °C

at different temperatures. Since quantitative

desorption of trapped molecules should ideally
be accomplished at moderate temperatures,
only weak adsorbing media are employed, with
active adsorbing surface between 10 and 50
k1>k
200 °C
times smaller than that of activated charcoal.
Use of thermal desorption requires therefore an
accurate preliminary investigation about the
adsorbed compound - adsorbing medium pair.
300 °C k

Stronger adsorbents are suitable for very volati-

le compounds, but will yield only partial desorp- concentration in gaseous phase (C)
tion of heavier compounds. When in contact with a solid adsorbing medium, a gaseous com-
pound will be adsorbed following the Freundlich isotherm, that is to
Anyway, backdiffusion (see page A3) is always lying
say the adsorbed mass will be x/m=kC1/n, where x is the mass of
in wait: due to the adsorbing medium weakness hea- gaseous compound adsorbed by the mass m of the solid adsor-
vier compounds will eventually displace the more bent and C is the concentration of the gaseous compound at the
volatile ones. Once you have made an accurate choi- equilibrium in the gas phase. K and n depend on temperature and
ce of the adsorbing material, therefore, you should on the adsorbate - adsorbing medium pair. K increases with
bear in mind that a real atmosphere is composed by decreasing temperature and n is the closer to 1 the stronger the
a variety of compounds apart from those you are adsorbent.
analyzing at unpredictable concentrations. As a con- At low temperatures, x/m depends almost linearly on the concen-
sequence, sampling times can not be as long as tration in air (see the curve at 25 °C): this allows diffusive sam-
those allowed by activated charcoal, otherwise lighter pling. At high temperatures, the adsorbent mass is very low wha-
tever the concentration in the gas phase: this allows the recovery
compounds will be lost. With the purpose of allowing
of adsorbed compounds by heating (see the curve at 300 °C).
reasonable sampling times (up to two weeks) the
To ensure the best possible recovery yields, k and n have to be
sampling rate has been dramatically reduced by small. This, however, will compromise sampling efficiency. In other
changing the diffusive body from the white type (code words, compounds strongly adsorbed at room temperature will be
RAD120) to the yellow one (code RAD1202). Smaller only partially recovered by thermal desorption. On the other hand,
average pore size and thicker diffusive membrane compounds that are easily desorbed by heating will be sampled at
make the diffusive path longer and, as a consequence, room temperature with low efficiency.

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Edition 01/2019

sampling rates are reduced to less than one third compared to those obtained with white diffusive bodies.
Some compounds, moreover, are thermally unstable. Thermal degradation of such com-
pounds will cause an underestimation of their concentration or the appearance of ghost
peaks.
Thermal desorption is neverthless an outstanding analytical technique because it is easy to
perform, it does not require the use of toxic solvents as carbon disulfide, it ensures very low
limits of detection, is suited to mass spectrometric detection and allows the recovery of the
adsorbing cartridges. Basing on our experience, we have chosen Carbograph 4 as the best
compromise between sampling efficiency and recovery yields for a wide range of organic
compounds.

Sampling rates
Sampling rate values at 298 K (25 °C) and 1013 hPa are listed in table on page E3. All of the values shown have
been experimentally measured. Exposure tests have been performed up to the levels shown (in µg·m-3·min) and
sampling rates are guaranteed to be linear up to the limit values and for overall concentration of volatile organic
compounds in air not exceeding 2,000 µg·m-3.

Effect of temperature, humidity and wind speed

Sampling rates varies from the value at 298 K on the effect of temperature (in Kelvin) as expressed by the following
equation

( )
K 1,5
QK = Q298
298

where QK is the sampling rate at the temperature K and Q298 is the reference value at 298 K. This produces a varia-
tion of ± 5% for 10 °C variation (upwards or downwards) from 25 °C.
Sampling rate is invariant with humidity in the range 15-90% and with wind speed between 0.1 and 10 m·s-1.
Do not expose directly radiello to rain: even if small amounts of water are adsorbed by Carbograph 4, they can neverthless
interfere with analysis.

Calculations
The listed sampling rate values take already into account the recovery yields of adsorbed compounds. The avera-
ge concentration over the sampling period is therefore calculated from sampled mass of analyte and exposure time
without introducing any other corrective factor, apart from temperature variations of Q.
Average concentration C in µg·m-3 over the whole exposure time is calculated according to the following expression:
m [µg]
C [µg·m-3] = 1,000,000
QK [ml·min-1] · t [min]
where:
m = mass of analyte in µg
t = exposure time in minutes

Exposure
Workplace environment
The use of ligth adsorbing media is not recommended in the workplace environment.

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 Edition 01/2019

Other indoor sampling experiments and outdoor campaigns

Thermal desorption is exceptionally suited for long exposure times at low concentrations, as in outdoor campaigns
and some indoor environments (e.g. homes, schools, etc...), particularly if the subsequent analysis is performed by
HRGC-MS.
The recommended exposure times range from 8 hours to the upper limits shown in the table below. It is advisable
to reduce sampling time if the estimated overall VOCs concentration is higher than 2,000 µg·m-3.

Sampling rate values at 25°C (298 K)

sampling rate exposure time linear up to uncertainty (2s) limit of detection1

ml·min-1 upper limit µg·m-3·min % µg·m-3
benzene 27.8 7 410,000 8.3 0.05
benzene 26.8 14 410,0002 7.5 0.05
butyl acetate 24.5 14 580,000 12.4 0.05
2-butoxyethanol 19.4 14 550,000 9.7 0.1
cyclohexane 27.6 7 470,000 14.7 0.1
n-decane 22.3 14 450,000 22.4 0.1
1,4-dichlorobenzene 22.0 14 650,000 9.5 0.1
dimethyl disulfide 23.7 7 500,000 9.1 0.04
n-heptane 25.3 14 420,000 7.6 0.05
n-hexane 25.5 7 420,000 10.9 0.05
ethylbenzene 25.7 14 550,000 9.1 0.01
ethyl-tert-butyl ether (ETBE) 30.0 7 600,000 - 0.1
2-ethyl-1-hexanol 14.3 14 550,000 17.4 0.07
2-ethoxyethanol 26.0 14 570,000 7.7 0.05
2-ethoxyethyl acetate 20.9 14 600,000 8.0 0.05
isopropyl acetate 25.8 7 540,000 9.6 0.1
limonene 12.8 14 550,000 24.8 0.2
methyl-tert-butyl ether (MTBE) 30.0 7 600,000 - 0.2
2-methoxyethanol 4.0 7 1,000,000 -- 1.0
2-metoxyethyl acetate 21.0 7 1,000,000 -- 0.1
1-methoxy-2-propanol 26.6 7 600,000 11.6 0.2
n-nonane 21.0 14 440,000 11.8 0.07
n-octane 24.1 14 440,000 13.4 0.07
a-pinene 6.4 14 550,000 29.5 0.2
styrene 27.1 14 550,000 24.0 0.01
tetrachloroethylene 25.4 7 1,000,000 8.9 0.02
toluene 30.0 14 550,000 8.3 0.01
1,1,1-trichloroethane 20.0 7 300,000 13.0 0.1
trichloroethylene 27.1 7 800,000 9.5 0.02
1,2,4-trimethylbenzene 21.9 14 550,000 9.6 0.05
n-undecane 12.0 14 520,000 32.7 0.05
m-xylene 26.6 14 550,000 11.3 0.01
o-xylene 24.6 14 550,000 9.1 0.01
p-xylene 26.6 14 550,000 11.3 0.01

1
after 7 days exposure and with MS detection; analytical conditions as described in the Analysis paragraph
2
for overall VOCs concentrations not exceeding 500 µg·m-3

Storage
The cartridges are thermally conditioned in a high temperature stove with an inert atmosphere, with an oxygen con-
tent lower than 10 ppm. The duration of the adsorbent capacity of graphitized carbon is virtually unlimited and has
been tested six months after production. Cartridges should be stored in a clean and solvent-free environment, in the
refrigerator or at room temperature. The expiry date and the lot number are printed on the transparent plastic casing,
whose integrity acts as a guarantee seal

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Edition 01/2019

Analysis
The methods proposed here have been elaborated with the Perkin-Elmer Turbomatrix thermal desorber coupled to
the Agilent 6890 gas chromatograph and Agilent 5973 mass spectrometer. They can naturally be transferred to other
instruments.
A method for BTEX and one for VOC are proposed here. The first refers to samples from urban air monitoring where
research is usually limited to benzene, toluene, ethylbenzene and xylene isomers. The second is more suitable for
indoor investigations, allowing the quantification of all the compounds listed in the table above and the more gene-
ral qualitative research, which also includes analytes with medium polarity.

Desorption
The thermal desorber is equipped with 1/4” s.s. sample tubes, they have to be hollow and free: discard the stain-
less steel gauze disk which is fitted to the groove and discard also the springs if present.
Code RAD145 cartridge has been dimensioned to fit the diameter of Turbomatrix thermal desorption tubes. Its
length is such that, when the cartridge is introduced into the tube and is stopped by the groove, it is positioned
exactly centrally with respect to the tube length. The same considerations apply to the Markes Unity thermal desorber.
Once capped, the Turbomatrix steel tube has to be positioned in the carousel with the grooves on the bottom.
The described conditions have been optimized for seven days exposures to typical concentrations of urban atmo-
spheres and indoor environments. Shorter exposure times or considerably higher concentrations would require dif-
ferent settings of split flows.

BTEX – detector FID

Temperatures and timing
• Desorption: 320 °C for 10 minutes, nitrogen flow through the tube 85 ml·min-1,
of which 35 ml·min-1 sent to the cryofocalization trap and 50 ml·min-1 to the inlet
split
• Cryofocusing trap (Tenax TA): adsorption 2 °C, desorption 99 °C·sec-1 up to 290
°C, 1 minute at 290 °C, trap desorption in nitrogen flow at 22.8 ml·min-1, of
which 22 ml·min-1 at the split outlet
• Six port valve: 150 °C
Usually, the cartridge enters
• Transfer line: 200 °C
into the Turbomatrix tube by
simple pouring. If it does not
Flows occur, use a pushing tool to
press the cartridge till the nick
• Carrier gas: helium, 24 psi on the tube.
• Desorption flow: 100 ml·min-1
• Inlet split: 90 ml·min-1
• Outlet split: 30 ml·min-1

Instrumental analysis
Column
J&W PONA, length 50 m, d.i. 0.2 mm, film thickness 0.5 µm; the column head can be connected directly to the
Turbomatrix six-way valve.
Temperatures
GC oven: 36 °C for 1 minute, 6 °C·min-1 up to 110 °C, mantain for 1 minute, 20 °C·min-1 up to 250 °C, final isotherm
5 minutes.
Flows
Carrier gas: nitrogen at 0.8 ml·min-1

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COV – detector MSD

Temperatures and timing
• Desorption: 350 °C for 10 minutes, helium flow through the tube 120 ml·min-1, of which 20 ml·min-1 sent to the
cryofocalization trap and 100 ml·min-1 to the inlet split
• Cryofocalization trap (Tenax TA): in adsorption 2 °C, in desorption 99 °C·sec-1 up to 290 °C, 1 minute at 290
°C, trap desorption in helium flow at 31 ml·min-1,
of which 30 ml·min-1 at the split outlet user tip
• Six port valve: 150 °C If you perform several analyses, a barcode reader
• Transfer line: 200 °C greatly improve productivity in your lab and will also
minimize the possibility of errors in the copying of sam-
ple labels.
Instrumental analysis
Please contact us to help you in the implementation of
Column
the reader.
J&W HP-5MS Ultra Inert or equivalent, length 60 m, d.i.
0.25 mm, film thickness 0.25 µm; the column head can
be connected directly to the Turbomatrix six-way valve.
Temperatures
• GC oven: 45 °C for 10 minute, 5 °C·min-1 up to 115 °C, 10 °C·min-1 up user tip
to 175 °C, 30 °C·min-1 up to 295 °C, final isotherm 6 minutes. For a very accurate BTEX cali-
Flows bration we offer the preloaded
cartridges code RAD407
Carrier gas: helium at 1.0 ml·min-1

Here, below, we display two total ion current chromatograms from an outdoor urban site and an indoor sampling
respectively.
In the first case, the benzene peak corresponds to an average concentration of 2.2 µg·m-3 ; in the second the con-
centration of 1,4-dichlorobenzene was 14 µg·m-3.

Calibration
Calibration curves are obtained by gas-phase injection of
methanol solutions of the target compounds onto blank
cartridges. Injections are performed through a GC injec-
tor, where a short piece (10 cm) of wide-bore (0.25 mm
i.d.) deactivated uncoated column is installed. The other
end bears a Swagelock reducing connection (1/16”-1/4”).
The 1/4” Swagelock nut has to be equipped with a PTFE
ferrule instead of the original steel one (use PTFE ferru-
les that come along with the Turbomatrix caps).
Introduce a blank cartridge in a Turbomatrix tube and fit
the tube to the Swagelock nut. Mantain the injector at 170
°C but do not heat the oven. Inject slowly 1 µl of each cali-
bration solution under nitrogen flow (40 ml·min-1) and let
the system purge for 2 minutes. Analyze the cartridge as
you would do with a sample. We suggest you to prepare
a complete set of calibration solutions by subsequent
dilutions such as they contain, for example, 8, 4, 2, 1, To prepare the calibration standards fit a 1/16”-1/4”
Swagelock reducing connection to the GC injector by a
0.04, 0.02 and 0.01 µg·µl-1 of each compound.
short piece (10 cm) of wide-bore deactivated uncoated
column.

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Edition 01/2019

TIC chromatograms of an
outdoor urban sampling (left)
and of indoor air (bottom).
Mass spectra of benzene and
of 1,4-dichlorobenzene are
shown on bottom of each pic-
ture, at concentrations of 2.2
and 14 µg·m-3 respectively.
Despite the low concentration
values, the signal-to-noise
ratio is very high in both
cases. As a consequence,
very reliable mass spectral
identification is possible by
comparison with mass spec-
tral data libreries with no
need of further processing.

Cartridge recovery
The cartridges can be recon-
ditioned using the thermal
desorber in "tube conditio-
ning" mode, heating them to
350 °C for at least 20 minutes
in an inert gas flow (helium or
nitrogen at a flow of 50 ÷ 100
ml·min-1).

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 Edition 01/2019

Nitrogen and sulfur dioxides (NO2 and SO2)

what you need
blue diffusive body code RAD1201
supporting plate code RAD121
vertical adapter code RAD122 (optional)
chemiadsorbing cartridge code RAD166

Principle
The cartridge code RAD166 is made of mycroporous polyethylene coated with triethanolamine (TEA). Nitrogen
(NO2) and sulfur (SO2) dioxide is chemiadsorbed onto TEA as nitrite and sulphite or sulphate ions respectively.
Nitrite is quantified by visible spectrophotometry while sulphite and sulphate are analysed by ion chromatography
(NO2 and SO2 can be analysed together by ion chromatography).
Sampling is selective for gaseous molecules: any airborne nitrite, sulphite or suplhate will not cross the diffusive
membrane.

Sampling rates
NO2
The sampling rate value Q298 at 298 K (25°C) and 1013 hPa is 0.141 ± 0.007 ng·ppb-1·min-1.

SO2
The sampling rate value Q298 at 298 K (25°C) and 1013 hPa is 0.466 ± 0.022 ng·ppb-1·min-1.

Effetto della temperatura, dell’umidità e della velocità dell’aria

Sampling rate of NO2 varies from the value at 298 K on the effect of temperature (in Kelvin) following the equation:
QK=Q298· K ( )
7,0

298
where QK is the sampling rate at the temperature K ranging from 263 to 313 K (from -10 to 40 °C) and Q298 is the
reference value at 298 K.
Sampling rate for SO2 does not vary with temperature between 263 and 313 K (from -10 to 40 °C).
Sampling rate is invariant with humidity in the range 15 - 90% and with wind speed between 0.1 and 10 m·s-1 for both
gases.

Calculations user tip

NO2 It is advisable to measure the
sampling temperature by the
The concentration CNO is calculated according to the equation:
2
mNO2 thermometer code RAD126.
CNO2 =
QK· t
where mNO is nitrite mass in ng found on the cartridge, t is exposure time in minutes and QK is the sampling rate value at
the temperature K in Kelvin.
2

SO2
Convert the sulphite found onto the cartridge into sulphate by multiplying its mass by 1.2, then sum the obtained value to
the sulphate found in the cartridge. The concentration in ppb is calculated according to the equation:
mSO4
CSO2 =
0.466· t
where mSO is the overall sulphate mass in ng found in the cartridge (sulphate itself and sulphite converted into sulphate)
and t is exposure time in minutes.
4

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Edition 01/2019

Exposure
Exposure up to 15 days is feasible but if relative humidity is higher than 70% for the entire sampling duration it is not
advisable to sample for more than 7 days. Due to the fact that TEA is very hygroscopic in fact, even if water does not
actually interfere with sampling or analysis, the excess water adsorbed by the cartridge could cause some loss of adsor-
bing medium by percolation.
WARNING: NO2 results may differ from those produced by automatic chemiluminescent instrumentation due to expo-
nential variation of the sampling rate of radiello with temperature. This phenomenon is characteristic of all NO2 samplers
that use TEA as an absorbent medium. The reason is not yet completely clear, but it is assumed that it depends in part
on the balance in the air between the species NO2 and N2O4, whose ratio is strongly linked to temperature: the TEA cap-
tures only the species NO2.

Limit of quantitation and uncertainty

Sampling rate of NO2 and SO2 is linear ranging from 10,000 to 5,000,000 ppb·min. Limit of quantitation after 7 days expo-
sure is 1 ppb for both gases. The uncertainty at 2s is 11.9% for NO2 and 9.2% for SO2.

Storage
The cartridges are stable for at least 12 months before and 4 months after the sampling, if kept in the dark at 4 °C.
Expiry date is printed on the plastic bag.
Do not expose all of the cartridges belonging to the same lot, keep at least two of them as blanks.

Analysis
Add 5 ml of water in the plastic tube with the cartridge and stir vigorously by a vortexer for 1 minute. Do the same
with two-three unexposed cartridges.
Colorimetric determination of nitrite ion
Nitrogen dioxide is quantitatively converted to nitrite ion. Prepare the following reactives:
• sulphanilamide: dissolve 10 g of sulphanilamide in 100 ml concentrated HCl and dilute to 1,000 ml with water
• NEDA: dissolve 250 mg of N-(1-naphthyl)ethylendiamine dihydrochloride in 250 ml of water (discard the solu-
tion when it turns brown).
Transfer 0.5 ml (or a different volume, see the table below) of the cartridge extraction solution to a plastic or glass
10 ml tube along with 5 ml of sulphanilamide reactive. Cap tigthly, stir and wait for 5 minutes. Add 1 ml of NEDA
reactive, stir and wait for 10 minutes. Do the same with unexposed cartridges.
Measure the absorbance of samples at 537 nm using water to zero the spectrophotometer, then subtract the blank
value from unexposed cartridges. Prepare the calibration standards in the same way from sodium nitrite solutions
of concentration ranging from 0.1 to 20 mg·l-1 expressed as NO2-.
When nitrite ion concentration is higher than 20 µg·ml-1 (corresponding to 7 days of exposure to 70 ppb) the absor-
bance value is no longer comprised in the average expected sample volume water volume
calibration curve. To analyse the samples, concentration for 7 ml to be added
draw smaller amounts of the extraction solu- days exposure in ppb ml
tion as shown in the table. In order to mantain
the overall volume unaltered, add the listed up to 70 0.5 0
volume of water. from 70 to 150 0.25 0.25
higher than 150 0.1 0.4

Determination of the sulphite and sulphate ions

Though SO2 is converted into sulphite and sulphate ions with variable ratios, the sum of the two ion equivalents is linear
with exposure to SO2. To obtain calibration curves, prepare solutions containing both ions at concentrations ranging
from 5 to 50 mg·l-1. Perform the ion chromatography analysis of the standard solutions and the extraction solutions from
radiello cartridges in the same way according to your usual laboratory practice.

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 Edition 01/2019

Ozone (O3)
What you need
blue diffusive body code RAD1201
supporting plate code RAD121
vertical adapter code RAD122 (optional)
chemiadsorbing cartridge code RAD172

Principle
The adsorbing cartridge is formed by a micropore polyethylene tube filled with silica gel coated with 4,4’-dipyridy-
lethylene and closed, at one end, by a PTFE cap. Upon exposure, acid-catalysed ozonolysis of 4,4’-dipyridylethy-
lene leads to 4-pyridylaldehyde. Silica gel ensures the presence of water, necessary to complete ozonolysis reactions.
+ O3

1,2-di(4-pyridyl)ethylene ozonure

+ H2O
2 + H2O2

In the laboratory, 4-pyridylaldheyde is condensed with 3-methyl-2-benzothiazolinone hydrazone (MTBH) to yield the
ozonure 4-pyridylaldehyde

corresponding azide, yellow coloured.

The absorbance of the solution is measured at 430 nm. Production of 4-pyridylaldehyde is a specific reaction of
ozone; neither nitrogen oxides nor organic compounds, if present, do interfere.

Sampling rate
The sampling rate value Q298 at 298 K (25°C) and 1013 hPa is 24.6 ml·min-1.
Sampling is linear in the exposure range from 10,000 to 4,000,000 µg·m-3·min-1.

Effect of temperature, humidity and wind speed

Sampling rate varies from the value at 298 K on the effect of temperature (in Kelvin) as expressed by the following equation:

QK= Q298 ( K
298
) 1.5

where QK is the sampling rate at the temperature K and Q298 is the reference value at 298 K.
Sampling rate is not influenced by humidity or wind speed.

Calculations
The average concentration over the whole exposure time is calculated according to the equation
m [µg]
C [µg·m-3] = 1,000,000
24.6 t [min]
where m is ozone mass in µg sampled by radiello and t is exposure time in minutes.

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Exposure
Introduce the cartridge in the diffusive body and make sure that the PTFE cap is positioned at the same end of
the screw.
In outdoor environments, where typical ozone concentrations range from 2 to 400 µg·m-3, we suggest exposure time
from 24 hours to 14 days. The ideal range is from 3 to 7 days.
In workplace environments it is advisable to sample over the entire 8 hours shift.

Limit of detection and uncertainty

The limit of detection is 2 µg·m-3 for 7 days exposures. The cartridge is saturated after 14 days exposure at 400
µg·m-3. The uncertainty at 2s is 14.5% over the whole sampling rate linearity range.

Storage
The cartridges need only protection from direct sunlight: keep them in a drawer or a cupboard at room temperatu-
re. In these conditions, the blank level does not exceed 0.015 absorbance units for up to six months.
Expiry date is printed onto the plastic bag wrapping each cartridge.
Generally, an increase of blank level does not imply that the cartridge must be discarded. The only consequence is
a corresponding increase of the analytical limit of quantification.
After exposure the samples have to be stored in the dark as before, along with three unused cartridges to be analy-
sed as blanks. Analyse them within a week.

Analysis
Reactives and materials user tip
• 3-methyl-2-benzothiazolinone hydrazone hydrocloride (MBTH): dissolve 5 g For a simple and accurate fil-
per litre in water and add 5 ml of concentrated sulphuric acid; this solution is to tration make use of the filtra-
be freshly prepared. tion kit code RAD174.
• 4-pyridylaldehyde
• micropore filter membrane 0.45 µm
IMPORTANT
Procedure
If the absorbance value is higher than the cali-
Draw the cartridge out from the plastic tube, discard the PTFE bration curve upper limit dilute the sample with
cap and pour the silica gel into the tube. Add 5 ml of MBTH the MBTH solution: never use water to dilute!
solution, recap the tube and stir vigorously. Let the tube stand Water alters the pH of the solution with unpre-
for at least one hour to react, stirring from time to time. Filter dictable variations in the linearity of absorbance
through the micropore filter (if you make use of the code 174, values vs concentration.
act as follows: fit the filter to the syringe, transfer the solution
from the tube to the syringe and filter it into a second tube or directly into the spectrophotometer measure cell).
Measure absorbance at 430 nm using water to zero the spectrophotometer. The yellow colour is stable for several
days if the solution is kept well capped in its tube.
Treat in the same manner three unused cartridges of the same lot and subtract the average blank value from the
absorbance values of the samples.

Calibration
Dissolve 100 µl (112.2 mg at 20° C) of 4-pyridylaldehyde in 1 litre of water and dilute this solution (e.g. 1:2, 1:5, 1:10)
to obtain calibration solutions. Transfer 0.5 ml of each calibration solution in a plastic tube together with 4.5 ml of MTBH
solution. Stir and let stand for one hour, then read the absorbance at 430 nm (filtration is not needed). Plot the cali-
bration curve for ozone mass vs measured absorbance, taking into account that:
1 µg of 4-pyridylaldehyde = 0.224 µg of ozone.

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 Edition 01/2019

Hydrogen sulfide (H2S)

What you need
blue diffusive body code RAD1201 or white code RAD120
supporting plate code RAD121
vertical adapter code RAD122 (optional)
chemiadsorbing cartridge code RAD170

Principle
The cartridge code RAD170 is made of microporous polyethylene and impregnated with zinc acetate. Hydrogen sul-
phide is chemiadsorbed by zinc acetate and transformed into stable zinc sulfide.
The sulfide is recovered by extraction with water. In contact with an oxidizing agent as ferric chloride in a strongly
acid solution it reacts with the N,N-dimethyl-p-phenylendiammonium ion to yield methylene blue.

NH2 H2N N
+ + H2S +
H3C N N CH3 H3C N S N CH3
H3C CH3 H3C CH3
H H FeCl3

N,N-dimethyl-p-phenylendiammonium Methylene blue

Methylene blue is quantified by visible spectrometry.

Sampling rate
Sampling rate Q298 at 298 K (25°C) and 1013 hPa is 0.096 ± 0.005 ng·ppb-1·min-1.

Effect of temperature, humidity and wind speed

Sampling rate varies from the value at 298 K on the effect of temperature (in Kelvin) as expressed by the following
equation:

QK= 0,096 ( 298

K ) 3,8

where QK is the sampling rate at the temperature K ranging from 268 to 313 K (from -5 to 40 °C).
Sampling rate is invariant with humidity in the range 10 - 90% and with wind speed between 0.1 and 10 m·s-1.

Calculations
Once QK at the sampling temperature has been calculated, the concentration C is obtained according to the equation:
m
C= 1,000
Q K· t
where m is the mass of sulphide ion in µg found onto the cartridge and t is exposure time in minutes.

Exposure
Exposure duration may vary from 1 hour to 15 days. Sampling is linear from 2,000 to 50,000,000 ppb·min of H2S.

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Limit of detection and uncertainty

The limit of detection is 30 ppb for 1 hour exposure or 1 ppb for 24 hour exposure. The uncertainty at 2s is 8.7%
over the whole exposure range.

Storage
The cartridges are stable at least for 12 months before and 6 months after exposure. Do not expose all of the car-
tridges of the same lot: keep at least two of them as blanks.

Analysis
Reactives and materials
• sulphuric acid: slowly add 25 ml of concentrated sulphuric acid to 10 ml water and let the solution cool;
• amine: dissolve 6.75 g of N,N-dimethyl-p-phenylendiammonium oxalate in the sulphuric acid solution. Dilute
this solution to 1 litre with sulphuric acid - water 1:1 v/v. Kept in a dark bottle and well capped, this solution is
stable for at least four weeks. CAUTION: this solution is very poisonous.
• ferric chloride: dissolve 100 g of ferric chloride hexahydrate (FeCl3·6H2O) in 40 ml of water.
• ferric chloride-amine: mix 10 ml of ferric chloride solution with 50 ml of amine solution. This solution has to be
freshly prepared;
• sulphuric acid for dilution: slowly dissolve 40 ml of concentrated sulphuric acid in 900 ml of water, let the solu-
tion cool and make up to 1,000 ml.

Procedure
Add 10 ml of water to the plastic tube containing the cartridge, recap and stir vigorously, preferably by a VORTEX
stirrer.
Add 0.5 ml of ferric chloride - amine solution, recap immediately and stir. The tube must be capped immediately in
order to avoid that the developed hydrogen sulfide can escape from the tube before reacting.
Wait for 30 minutes and measure absorbance at 665 nm using water to zero the spectrophotometer. The colour is
stable for several weeks.
Do the same with two or three unexposed cartridges of the
same lot and obtain the average blank value, then subtract it to IMPORTANT
the samples. Absorbance is linear up to 1,200 absorbance
units, corresponding to an exposure value of
about 80,000 ppb·min. If higher absorbance
Calibration values are obtained, dilute the samples with the
sulphuric acid for dilution.
Calibration curves may be prepared by sodium sulfide standard
solutions, which have to be titrated just before use. As diluted Be careful to apply the same dilution ratio to the
sodium sulfide solutions are very unstable (the sulfide content samples and the blanks.
can diminish as much as the 10% in an hour) it is strongly NEVER USE WATER TO DILUTE.
recommended to make use of the calibration solution code
RAD171, following the instructions included.

user tip
Code RAD171 calibration
solution relieves you from the
task of preparation and titration
of the sodium sulfide solutions.

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 Edition 01/2019

Ammonia (NH3)
What you need
blue diffusive body code RAD1201 or white code RAD120
supporting plate code RAD121
vertical adapter code RAD122 (optional)
chemiadsorbing cartridge code RAD168

Principle
The cartridge code RAD168 is made of microporous polyethylene and impregnated with phosphoric acid. Ammonia
is adsorbed as ammonium ion. Airborne ammonium salts dispersed as particulate matter do not cross the diffusive
membrane of radiello.
Ammonium ion is quantified by visible spectrometry as indophenol: at basic buffered pH ammonium ion reacts with
phenol and sodium hypochlorite, with pentacyanonitrosylferrate catalysis (in the following cyanoferrate), to form
indophenol. The reaction product is intensely coloured in blue, and its absorbance measured at 635 nm.

NaClO
HO + NH3 + OH O N ONa
Na2Fe(CN)5NO.2H2O
(cyanoferrate)

indophenol

Sampling rate
Sampling rate Q298 at 298 K (25°C) and 1013 hPa is 235 ml·min-1.

Effect of temperature, humidity and wind speed

The effect of temperature on sampling rate is negligible (<0.1%/°C) in the range from 275 ÷ 312 K (2 ÷ 39 °C).
Sampling rate is invariant with humidity in the range 10 - 90% and with wind speed between 0.1 and 10 m·s-1.

Calculations
The concentration C in µg·m-3 is obtained according to the equation:
m
C = 0.944 1,000,000
235· t
where m is the mass of ammonium ion in µg found onto the cartridge and t is exposure time in minutes.
0.944 is the numerical factor necessary to convert ammonium ion into ammonia (see Analysis)

Exposure
IMPORTANT
Introduce the cartridge in the diffusive body and make sure that the
PTFE cap is positioned at the same end of the screw. Do not touch the microporous portion
of the cartridge with your fingers:
Ammonia is sampled linearly in the range from 2,000 - 20,000,000 µg·m-3·min. sweat contains ammonium ions.
Exposure time is allowed to range from 1 hour to 14 days.

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Edition 01/2019

Limit of detection and uncertainty

The limit of detection is 1 µg·m-3 for 24 hour exposure. The uncertainty at 2s is 6.5% over the whole allowed expo-
sure range.

Storage
The cartridges are stable at least for 12 months before and after exposure if kept at room temperature in an ammo-
nia-free environment. Do not expose all of the cartridges of the same lot: keep at least two of them as blanks.

Analysis
Materials
• plastic or glass tube, volume 12 ml, with cap
• micropipet with variable volume from 0.1 to 1.0 ml
• 5 ml glass pipet

Reactives
• buffer solution (pH 10.6): dissolve 1.1 g of NaOH and 3.04 g of NaHCO3 in one litre of water
• phenol: dissolve 10 g of phenol in 100 ml of ethanol
• cyanoferrate: dissolve 0.5 g of sodium pentacyanonitrosylferrate dihydrate (Na2Fe(CN)5NO·2H2O) in 100 ml of
water and add a few drops of 10% NaOH. Keep this solution in a dark bottle and prepare it freshly.
• oxidising solution: sodium hypochlorite with 1% of active chlorine in 0.2 M NaOH. Keep cool in a dark bottle.

Ammonium ion quantification

Open radiello tube and cautiously discard the cartridge PTFE cap (it may have been contaminated with handling).
Help yourself with a pair of pliers.
Add 10 ml of deionised water to the cartridge in its tube (make sure that no trace of ammonium ion is found in the
water you use). Recap the tube and stir vigorously by a VORTEX stirrer for at least 15 seconds.
Transfer 1 ml of the solution into another tube along with 0.4 ml of phenol, 0.4 ml of cyanoferrate, 5 ml of buffer solu-
tion and 1 ml of oxidising solution.
Wait for 1 hour and then measure the absorbance of the solution at 635 nm using water to zero the spectrophoto-
meter.
Do the same with two unexposed cartridges and subtract their absorbance value to the samples. Generally, the
blank value does not exceed 0.040 absorbance units.
For exposure value higher than 500,000 µg·m-3·min the absorbance
value is no longer linear: diluite a known fraction of the coloured IMPORTANT
solution with the buffer.
If sample is too concentrated (absorbance
Calibration curves are conveniently prepared with ammonium chlo- no longer linear) DO NOT DILUTE WITH
ride solutions in the range from 0.5 to 10 mg·l-1 as ammonium ion. WATER: the pH value is critical in the
determination of the colour intensity.

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Hydrochloric acid (HCl)

What you need
blue diffusive body code RAD1201 or white code RAD120
supporting plate code RAD121
vertical adapter code RAD122 (optional)
chemiadsorbing cartridge code RAD169

Principle
Code RAD169 cartridge is made of stainless steel net loaded with silica gel (0.1 to 0.4 mm particle size). Gaseous
hydrochloric acid is adsorbed by silica gel and subsequently extracted with water to be quantified by ion chromato-
graphy as chloride ion.
Sampling is selective for the gaseous molecules: any airborne chloride salt will not cross the diffusive membrane of
radiello.

Sampling rate
Sampling rate (Q298) at 25 °C (298 K) and 1013 hPa is 103 cm3·min-1.

Effect of temperature, humidity and wind speed

Sampling rate varies from the value at 298 K (25 °C) on the effect of temperature (in Kelvin) as expressed by the
following equation:

QK = 103 ( 298
K
) 1,5

where QK is the sampling rate at temperature K and Q298 is the sampling rate value at the reference temperature of
298 K. This yields a ± 5% variation of Q for a 10 °C variation (upwards or downwards) from 25 °C.
Sampling rate is invariant with humidity in the range 15 - 90% for short exposure time (see Exposure) and with wind speed
between 0.1 and 10 m·s-1.

Calculations
Let m be the mass of chloride ion in µg found onto the cartridge and t the exposure time in minutes, the environmental
concentration C of hydrochloric acid in µg·m-3 is obtained according to the equation:
1.028 m 1,000,000
C=
QK t
where QK is the sampling rate at temperature K (in Kelvin) and 1.028 is the ratio between molecular masses of HCl
and Cl-(see Analysis).

Exposure
Hydrochloric acid is sampled linearly in the range from 20,000 ÷ 20,000,000 µg·m-3·min.

Workplace environment
In workplace environment we recommend exposure time from 15 minutes to 8 hours: the ceiling values can be mea-
sured.

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Outdoor environment
We recommend exposure time from 2 hours to 2 days. Exposure time as long as 7 days is allowed if average rela-
tive humidity does not exceed 50%, taking into account the water absorbing properties of silica gel.
We also recommend to protect radiello from rain by the mountable shelter code RAD196.

Limit of detection and uncertainty

The limit of detection is 10 µg·m-3 for 24 hour exposure. The uncertainty at 2s is 3.5% over the whole allowed expo-
sure range.

Interferences
Gaseous chlorine is adsorbed by silica gel and is revealed as 0.02 ng of chloride ion for 1 µg·m-3·min of chlorine.

Storage
Kept in a clean environment free from gaseous hydrochloric acid, the cartridges code 169 are stable for at least 24
months before and after sampling.
If more than six months have passed since you received the cartridges, before environmental sampling campaigns,
it is advisable to analyse some cartridges to check for contamination from the background. Discard the cartridges if
they contain more than 5 µg of chloride ion.

Analysis
Add 2 ml of deionised water to the cartridge in its tube (make sure that no trace of chloride ion is found in the water
you use). Recap the tube and stir vigorously by a VORTEX stirrer for 1-2 minutes. Analyse the solution by ion chro-
matography. Subtract the blank value obtained from two unexposed cartridges.
Prepare the calibration solutions with sodium or potassium chloride concentrations ranging from 0.5 to 25 mg/litre
as Cl-.

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Hydrofluoric acid (HF)

What you need
blue diffusive body code RAD1201 or white code RAD120
supporting plate code RAD121
vertical adapter code RAD122 (optional)
chemiadsorbing cartridge code RAD166

Principle
The cartridge code RAD166 is made of microporous polyethylene coated with triethanolamine (TEA). Gaseous
hydrofluoric acid is adsorbed by TEA and subsequently extracted with water to be quantified by ion chromatography
or by ion selective electrode as fluoride ion.
Sampling is selective for the gaseous molecules: any airborne fluoride salt will not cross the diffusive membrane of
radiello.

Sampling rate
Sampling rate at 25 °C and 1013 hPa is 187 cm3·min-1.

Effect of temperature, humidity and wind speed

Sampling rate is invariant with humidity in the range 10 - 90% for short exposure time (see Exposure) and with wind speed
between 0.1 and 10 m·s-1. The effect of temperature is under investigation.

Calculations
Let m be the mass of fluoride ion in µg found onto the cartridge and t the exposure time in minutes, the environmental
concentration C of HF in µg·m-3 is obtained according to the equation:
1.053 m 1,000,000
C=
187 t
where 1.053 is the ratio between molecular masses of HF and F-(see Analysis).

Exposure
Hydrofluoric acid is sampled linearly in the range from 10,000 to 50,000,000 µg·m-3·min.

Workplace environment
In workplace environments we recommend exposure time from 15 minutes to 8 hours: the ceiling values can be
measured.

Outdoor environment
We recommend exposure time from 2 hours to 14 days.
Protect radiello from rain by the mountable shelter code RAD196.

Limit of detection and uncertainty

The limit of detection is 7 µg·m-3 for 24 hour exposure. The uncertainty at 2s is 4.5% over the whole exposure range.

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Storage
Kept in a dark place at 4 °C, the cartridges stay unaltered for at least 12 months before exposure and 4 months after
sampling. Expiry date is printed on the plastic bag wrapping each cartridge.
If more than six months have passed since you received the cartridges, before environmental sampling campaigns,
it is advisable to analyse some cartridges to measure any contamination from the background. Discard the cartrid-
ges if they contain more than 2 µg of fluoride ion.
Keep at least two unexposed cartridges for each lot and analyse them as blanks.

Analysis
Ion chromatography
Add 5 ml of the eluent solution to the radiello tube. Stir vigorously by a VORTEX stirrer for 1-2 minutes. Let the tube
stand for 10 minutes, then stir manually and inject the solution in the ion chromatographic apparatus without further
treatment.
Analyse 1-2 unexposed cartridges and subtract the average blank value to the samples.

Ion Selective Electrode

Prepare an ionic strength buffer as follows. Dissolve 57 ml of acetic acid in 500 ml water and add 50 g of sodium
chloride and 0.3 g of sodium citrate. When complete solubilisation has been achieved, adjust the pH value to 5-5.5
(ideal value is 5.3) by adding drops of 10 M sodium hydroxide. Make up to 1 litre with water.
Add 5 ml water to radiello tube and stir vigorously by a vortexer for 1-2 minutes, then let stand for 10 minutes.
Introduce a magnetic stirring bar in a 20 ml beaker, add 10 ml of
ionic strength buffer and 1 ml of the extraction solution of the car-
tridge. Start the magnetic stirrer and make the potentiometric mea- IMPORTANT
surement by an ion selective electrode for fluorides. In the described Always use water with fluoride content
analytical conditions, the electrode response should be linear in the lower than 0.5 mg·l-1.
range from 1 to 1,000 mg·l-1 of F with slope close to 59 ± 0.5 (if
-

potential is expressed in mV).

Analyse 1-2 unexposed cartridges and subtract the average blank value to the samples.

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Anaesthetic gases and vapours

N2O, isoflurane, ethrane, halothane and sevorane
What you need
Sampling kit code RAD125, containing 20 single packages each composed of:
1 permeative body (code RAD1203)
1 supporting plate (code RAD121)
1 vertical adapter (code RAD122)
1 adsorbing cartridge (code RAD132)
the listed components are contained in a closed aluminum envelope, which is wrapped
by a thermowelded paper-polyethylene bag.
The whole is sterilized by g-rays.
The single components are also available non-sterilized in 20 pieces per package.

Principle
Code RAD132 cartridge is made of stainless steel net loaded with a mixture of molecular sieve and activated char-
coal 35-50 mesh.
Nitrous oxide and halogenated anaesthetic gases permeate the silicone membrane and are sampled by the molecu-
lar sieve and by activated charcoal respectively.
The sampled compounds are displaced by a water-methanol mixture and are quantified by capillary gas chromato-
graphy and a headspace sampler.
N2O, isoflurane, ethrane and halothane are detected by the Electron Capture Detector (ECD) with very good sensiti-
vity; sevorane can not be quantified by ECD detection and has to be analyzed by mass spectrometry.

Sampling rate
Sampling rate values at 25 °C (298 K) and 1013 hPa are listed in the table on the right.
sampling rate
Effect of temperature, humidity and wind speed (ml·min-1)
Sampling rate varies from the values at 298 K on the effect of tem-
perature (in Kelvin) as expressed by the following equation: N 2O 1.01

isoflurane 2.25
QK = Q298 ( 298
K
) 1.5

ethrane 3.39
where QK is the sampling rate at temperature K and Q298 is the sam-
pling rate value at reference temperature of 298 K. This yields a ± 5% halothane 4.93
variation of Q for a 10 °C variation (upwards or downwards) from 25
°C. sevorane 0.92
Sampling rate is invariant with humidity in the range 10 ÷ 90% for expo-
sure time not exceeding 8 hours and with wind speed between 0.1 and
10 m·s-1.

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Calculations
Concentration in air is obtained by the following equation:
C = m· 1,000
QK·t
where:
C = concentration in mg·m-3
m = mass of analyte found on the cartridge in µg
QK = sampling rate in ml·min-1
t = exposure time in minutes

Exposure
Sampling rate is constant for exposure time up to 8 hours at relative humidity up to 80% with N2O concentration up
to 500 ppm and overall halogenated anaesthetic compounds concentration up to 100 ppm.
Exposure time longer than 8 hours in presence of relative humidity higher than 80% leads to the loss of the nitrous
oxide already sampled by the effect of competing water vapour adsorption on the molecular sieve sites.

Limit of detection and uncertainty

The cartridges are conditioned to ensure a chromatographic blank level lower than three times the instrumental
noise at the minimum attenuation.
If a well conditioned ECD is employed, 4 hours of exposure ensure the following analytical sensitivities: 0.5 ppm of
N2O, 0.002 ppm of isoflurane, 0.01 ppm of ethrane and 0.002 ppm of halothane. Sevorane is not detected by ECD.
The Flame Ionisation Detector (FID) can be employed instead with acceptable sensitivity, but if nitrous oxide and
the other halogenated compounds have to be quantified at the same time, a mass spectrometry detector must be
used. Acquiring by the SIM (Single Ion Monitoring) technique detection limits close to the ECD performances can
be achieved for N2O, isoflurane, ethrane and halothane. For sevorane, 1 hour exposure allows to detect 0.1 ppm.
The uncertainty at 2s is: 5.5% for N2O, 4.7 - 5.6% for isoflurane, ethrane and halothane with ECD detection, 6.2%
for N2O and 5.5 - 6.2% for isoflurane, ethrane, halothane and sevorane with MS detection.

Storage IMPORTANT
The sampling kit code RAD125 is sterilized by g-rays. Use of DO NOT STERILIZE THE SAMPLER BY
the sampler makes it no longer sterile. With the exception of the AUTOCLAVING. Autoclaving treatment perma-
adsorbing cartridge, the sampler is indefinitely re-usable. After nently damages the silicone permeative mem-
the first sampling, if you can arrange for sterilization by your- brane.
selves you only need to re-order code RAD132 cartridges to
perform other sampling campaigns. Adsorbing cartridges need not to be sterile.
If kept in a dry place free from chemical contamination, the cartridges are stable for at least 12 months.
After the sampling, the cartridges are stable for 30 days if stored with the same precautions.

Analysis
Materials needed for the analysis
• 20 ml headspace glass vials with open-top aluminum crimp caps and rubber/PTFE septa
• water/methanol mixture 60/40 v/v
• usual laboratory glassware

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Materials needed for the calibration curve

• pure N2O in a gas cylinder

• halogenated anaesthetic compounds
• gastight syringe (volume 500 µl) and other syringes (volume 100 and 10 µl)
• 1 litre glass bottle with threaded neck, equipped with open-top screw cap and rubber/PTFE septum (the volu-
me of the bottle must be precisely measured and the bottle must be rinsed with dry nitrogen before use)
• magnetic stirrer with large magnetic stirring bar (about 30-40 mm long)
• usual laboratory glassware
Extraction
Introduce 10 ml of water/methanol mixture in a headspace vial by a volumetric pipette. Add the radiello cartridge and cap
immediately. Stir and let equilibrate, place the vial in the headspace bath and let equilibrate for one hour at 45 °C.
Instrumental analysis
ECD detection (sevorane is not detected)

• vial pressurization gas: N2 at 1.2 atm

• loop volume: 1 ml
• gas chromatographic column: polystyrene-divinylbenzene PLOT, 30 m long, 0.32 mm inner diameter, 20 µm
film thickness (allows quantification of nitrous oxide and other anaesthetic gases in one chromatographic run)
• carrier gas: N2 at 1.0 atm
• split ratio: 10/1
• make-up gas: Ar-CH4 (CH4 10% v/v) at 30 ml·min-1
• GC oven: 40° C for 2 min, 10° C·min-1 up to 150° C, 6° C·min-1 air ECD Analyis
up to 200° C, final isotherm for 5 minutes
N2O 110 ppm
• injector temperature: 150° C
• detector temperature: 300° C

alothane 0.02 ppm

isoflurane 0.75 ppm
In the described analytical conditions chromatogram similar to the

ethrane 0.75 ppm

one in the figure are obtained. In the example shown, exposure

water impurity
time was 4 hours at the concentration values indicated and with methanol
relative humidity of 70%.
water

MS detection

The instrumental conditions are as described above, with the exception of the carrier gas (helium has to be used
instead) and the make-up gas, which is not employed. Acquire by SIM (Single Ion Monitoring) focussing the detec-
tor on the following signals (the base peak is underlined):
N2O: 44; isoflurane and ethrane: 51, 67, 117; halothane: 117, 198, 179; sevorane: 33, 131, 181
If high concentrations of CO2 interfere (it gives a strong signal at m/z 44), N2O can be quantified basing on the signal
at m/z 30. On page L4 a typical GC-MS chromatogram (as total ion current) is displayed. It can be observed that,
as an effect of the vacuum applied on the detector end of the column, retention times are shorter with respect to
those obtained with ECD detection.

Calibration
Calibration curves for N2O and halogenated anaesthetics can be prepared simultaneously.
Draw pure N2O in a gas sampling bulb. Transfer 20 ml of pure N2O in the 1 litre bottle through the septum by a
gastight syringe. Switch on the magnetic stirrer and let the mixture equilibrate for 30 minutes.

Standard solutions of the halogenated compounds must be prepared in water/methanol 60/40 v/v in order to con-

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MSD Analysis

ethrane
isoflurane
air

N 2O

halotane
sevorane
time (min)

tain from 0.05 to 3.0 mg/l of each compound; five calibration levels are recommended.
For each level pipet 10 ml of calibration solution in an empty vial, add a blank code 132 cartridge and cap imme-
diately.
Add also a precisely measured volume of diluted N2O drawn from the bottle by a gastight syringe (usually added
volume ranges from 50 to 1,000 µl), stir and let equilibrate at 45 °C for 1 hour.

The values above generally comprise the usual conditions of operating theatres. The analyst may choose different
values if needed, but equivalent exposure values should not exceed 400,000 mg·m-3·min for nitrous oxide and 50,000
mg·m-3·min for each of the halogenated compounds.
Pay attention: the ECD and/or MSD response may not be linear. If this should be the case, use a second order cali-
bration curve.

Useful data
name chemical formula molecular weight 1 mg·m-3 at 25°C = ppm
nitrous oxide N 2O 44 0.556
forane CHF2-O-CHCl-CF3 184.5 0.133
ethrane CHF2-O-CF2-CHClF 184.5 0.133
halothane CF3-CHBrCl 197.4 0.124
sevorane CH2F-O-CH(CF3)2 200 0.123

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phenol, methylphenol and dimethylphenol

(thermally desorbed)
What you need
white diffusive body code RAD120
supporting plate code RAD121
vertical adapter code RAD122 (optional)
chemiadsorbing cartridge code RAD147

Principle
Code RAD147 cartridge is a stainless steel net cylinder with 100 mesh opening and 4.8 mm diameter, packed with
250 ± 10 mg of Tenax-TA, particle size 20-35 mesh. Phenols are trapped by adsorption and recovered by thermal
desorption, analysis is performed by capillary gas chromatography and MS detection.
The method has been optimized for the following compounds:
OH OH OH OH OH
CH3 CH3

CH3 CH3
phenol o-cresol m-cresol 2,3-dimethylphenol
CH3
p-cresol

OH OH OH OH
CH3 H3C CH3

H3C CH3 H3C CH3

2,5-dimethylphenol 2,6-dimethylphenol CH3 3,5-dimethylphenol

3,4-dimethylphenol

Sampling rates sampling limit of uncer-

rate detection1 tainty
Sampling rate values (in ml·min-1) at 298 K (25 °C)
ml·min-1 µg·m-3 at 2s %
and 1013 hPa are listed in the table on the right. All
of the values shown have been experimentally mea- phenol 38 0.3 24.1
sured.
o-chresol 45 0.4 17.5
Effect of temperature, humidity and wind speed
m-chresol 48 0.4 8.0
Sampling rates varies from the value at 298 K on the
effect of temperature (in Kelvin) as expressed by the p-chresol 48 0.4 8.0
following equation
2,3-dimethylphenol 53 0.4 26.0
QK = Q298 ( K
298
) 1.5

2,5-dimethylphenol 51 0.3 25.2

where QK is the sampling rate at the temperature K 2,6-dimethylphenol 46 0.4 7.6
and Q298 is the reference value at 298 K.
This produces a variation of ±5% for 10 °C variation 3,4-dimethylphenol 60 0.4 22.1
(upwards or downwards) from 25 °C.
Sampling rate is invariant with humidity in the range 15 3,5-dimethylphenol 61 0.4 22.2
÷ 90% and with wind speed between 0.1 and 10 m·s-1.
riferita ad esposizione di 24 ore e misurata con rivelatore a spettrometro di massa
1

nelle condizioni di desorbimento descritte in Analisi

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Calculations
The listed sampling rate values take already into account the recovery yields of adsorbed compounds. The avera-
ge concentration over the sampling period is therefore calculated from sampled mass of analyte and exposure time
without introducing any other corrective factor, apart from temperature variations of Q.
Average concentration C in µg·m-3 over the whole exposure time is calculated according to the following expression:
m [µg]
C [µg·m-3] = 1.000.000
QK [ml·min-1] · t [min]
where:
m = mass of analyte in µg
t = exposure time in minutes

Exposure
Workplace environment
Exposure time can range from 2 to 8 hours.

Other indoor sampling experiments and outdoor campaigns

The recommended exposure times range from 8 hours to 7 days.

Storage
The duration of Tenax adsorbent capacity is virtually unlimited. If kept in a cool place not contaminated by phenols,
white and adsorbent capacity remain unchanged for at least twenty-four months. The expiry date and the lot num-
ber are printed on the transparent plastic casing, whose integrity acts as a guarantee seal.
After exposure the cartridges, well capped and kept in a cool and solvent-free place, maintain their content unalte-
red for at least three months.

Analysis
The analytical method hereafter described have been set up by the Perkin-Elmer Turbomatrix thermal desorber and
Agilent 5973 MSD mass spectrometer detector. They may be implemented on other instruments by introducing
minor adjustements.

Desorption
The thermal desorber is equipped with 1/4” s.s. sample tubes, they have to be hollow and free: discard the stain-
less steel gauze disk which is fitted to the groove and discard also the springs if present.
Code 147 cartridge has been dimensioned to fit the diameter of Turbomatrix thermal desorption tubes. Its length is
such that, when the cartridge is introduced into the tube and is stopped by the groove, it is positioned exactly cen-
trally with respect to the tube length. The same considerations apply to the Markes Unity thermal desorber.
Once capped, the Turbomatrix steel tube has to be positioned in the carousel with the grooves on the bottom.
The desorption conditions described below have been developed to obtain the best results from cartridges expo-
sed for seven days to the usual concentrations of urban and indoor pollution. Shorter exposure times or much higher
concentrations than usual may make it necessary to readjust the splits.
Temperatures and timing
• Desorption: 280°C for 10 minutes
• Cryofocusing trap (Tenax TA): during primary desorption maintain at 2 °C, secondary desorption at 99 °C·sec-1
up to 290 °C, maintain at 290 °C for 1 minute
• Six port valve: 150 °C
• Transfer line: 200 °C

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Flows
• Carrier gas: helium, 24 psi
• Desorption flow: 100 ml·min-1
• Flow from tube to cryofocusing trap: 20 ml·min-1
• Outlet split: 25 ml·min-1

Instrumental analysis
Column
J&W HP-5MS Ultra Inert or equivalent, length 60 m, internal diameter 0.25 mm, film thickness 0.25 µm; the column
is directly fitted to the six-port valve of Turbomatrix apparatus

Temperatures
• GC oven: 40 °C for 5 minutes, 5 °C·min-1 up to 115°C, 10 °C·min-1 up to 165 °C, 30 °C·min-1 up to 285 °C, final
isotherm 3 minutes
• GC-MS interface: 260 °C
•

Flows
• helium carrier gas: 1.6 ml·min-1
•

In the figure on the right a typical

chromatogram (as total ion cur-
rent) is shown.

Calibration
Calibration curves are obtained
by gas-phase injection of metha-
nol solutions of the target com-
pounds onto blank cartridges.
Injections are performed through
a GC injector, where a short piece
of wide-bore (0.53 mm i.d.) deac-
tivated uncoated column is instal-
led. The other end bears a
Swagelock reducing connection
(1/16”-1/4”).
The 1/4” Swagelock nut has to be
equipped with a PTFE ferrule
instead of the original steel one
(use PTFE ferrules that come along with the Turbomatrix caps).
Introduce a blank code RAD147 cartridge in a Turbomatrix tube and fit the tube to the Swagelock nut. Keep the
injector at 170 °C but do not heat the oven. Inject slowly 1 µl of each calibration solution under nitrogen flow (40 ml·min-1)
and let the system purge for 2 minutes. Analyze the cartridge as you would do with a sample. We suggest you to
prepare a complete set of calibration solutions by subsequent dilutions such as they contain, for example, 4, 2, 1,
0.05, 0.025 and 0.01 µg·µl-1 of each compound.

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Recupero delle cartucce

The cartridges can be reconditioned using the thermal
desorber in tube conditioning mode, heating them at 280
° C for at least 20 minutes in an inert gas flow (helium or
nitrogen at a flow of 50 ÷ 100 ml·min-1).

To prepare the calibration standards fit a 1/16”-1/4”

Swagelock reducing connection to the GC injector
by a short piece of wide-bore deactivated uncoated
column.

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1,3-butadiene and isoprene

What you need
yellow diffusive body code RAD1202
supporting plate code RAD121
vertical adapter code RAD122 (optional)
chemiadsorbing cartridge code RAD141

Principle
Cartridge code RAD141 is a 4.8 mm diameter stainless steel mesh tube with a mesh size of 3x8 µm, filled with
approximately 480 mg of graphite carbon (Carbopack X) 40/60 mesh.
1,3-butadiene and isoprene are trapped by adsorption, recovered by thermal desorption and analysed by capillary
gas chromatography with MS detector.

Sampling rates
Sampling rate values were measured experimentally at 20°C (273 K) and 1013 hPa in a dynamic controlled atmo-
sphere chamber.
The sampling rate for 1,3-butadiene in the workplace is 30.5 ± 0.3 ml·min-1 (nominal value at a concentration bet-
ween 114 and 226 µg·m-3 for 8-hour exposures). For the longer term (7 days) sampling the value is 4.7 ml·min-1
[Strandberg et al. (1), (2)].
For isoprene the sampling rate is 41.2 ± 4.9 ml·min-1 (in the range 2 ÷ 6,680 µg·m-3 for exposures of 30 to 480 min).

Effect of temperature, humidity and wind speed

Both temperature and relative humidity affect the sampling rate of 1,3-butadiene. If the temperature drops to 5 °C,
the bias is + 12.9% at 20% RH or -2.4% at 80% RH, compared to 20 °C and 50% RH. Avoid sampling at tempera-
tures close to 40 °C, as the sampling rate shows a significant decrease.
The effect of temperature and relative humidity on the isoprene sampling rate is lower: at low temperature and humi-
dity (5°C, 21% RH) the sampling rate is 10% higher, while at high temperature and humidity (41°C, 77% RH) there
is a 23% decrease.
Do not expose the sampler directly to rain. Always use the weather box code RAD196 for outdoor sampling to pre-
vent water from entering the membrane and bathing the absorbent.

Calculations
The average concentration C over the exposure time interval is calculated from the mass of the analyte found on
the cartridge (corrected for the white, if any) and from the exposure time, using the absorption values above, as fol-
lows:
m [µg]
C [µg·m-3] = 1,000,000
QK [ml·min-1] · t [min]
where:
m = mass of analyte in µg
t = exposure time in minutes

(1) Strandberg et al. Atmos. Environ., 2006. 39(22), 4101-4110.

(2) Strandberg et al. Atmos. Environ., 2006. 40(40), 7686-7695.

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Limit of detection
The blank response, the limit of detection (LOD) and the limit of quantification (LOQ) depend on the instrumenta-
tion and the analytical conditions.
Under the analytical conditions specified below, the blank value is not detectable, i.e. it is less than 0.5 ng for both
compounds.
The LOQ for 8-hour workplace exposure is 0.1 µg·m-3. For a 7-day exposure to ambient air, the LOQ is 0.03 µg·m-3;
see also Strandberg et al. (2).

Measurements uncertainty
The following table shows the values of uncertainty in 1,3-butadiene measurements in the workplace, evaluated with
two different approaches. Uncertainties were first determined under laboratory conditions, following the methods of
the ISO GUM (Guide to Expression of Uncertainty in Measurement, International Organization for Standardization)
and ISO 5725
(Accuracy (trueness Uncertainty of measurement for an 8-hour sampling of 1,3-butadiene in working environment
and precision) of Relative combined 200 µg·m-3 442 µg·m 2210 µg·m-3 4420 µg·m-3
-3

measurement expanded uncertainty (0.1 TLV) (0.5 TLV) (TLV-TWA ACGIH)

methods and results (2·uc)
General principles
and definitions) Laboratory tests
standards. In this at 20 °C, 50% RH
48.4%
case, the uncer- (EN 838, calculations by
tainty takes into ISO GUM)
account all the con-
Field comparison
tributions involved in 37.0% 25.0% 11.1% 7.9%
(ISO 13752)
the whole measure-
ment process (time,
T, RH on the sampling rate, uncertainty of the measured mass and so on), contributions which were determined
according to EN 838. Subsequently, the uncertainty was determined by a field comparison with OSHA 56 (as a refe-
rence method), according to ISO 13752.

Storage
After the exposure, the samples, well capped in their glass tubes, have to be stored in the freezer, because 1,3-
butadiene and isoprene are reactive compounds. Laboratory tests according to EN 838 showed for both compounds
a loss of analyte of 7-8% after 14-day storage. The samples shall therefore be analysed within 14 days from the end
of exposure, in order to ensure the maximum loss of analyte remain within 10%.

Analysis
The method proposed here was developed with the Perkin-Elmer Turbomatrix thermal desorber coupled to the
Agilent 6890 gas chromatograph and Agilent 5973 mass spectrometer. It can of course be transferred to other instru-
ments.

Desorption
The 1/4 "pipe supplied with the Turbomatrix must be empty and free: remove the stainless steel disk placed inside
it in correspondence with the circular incision and, if present, also the springs.
The code 141 cartridge has been sized so that its outer diameter coincides with the inner diameter of the
Turbomatrix tube. Moreover, its length is such that, when the cartridge is introduced into the tube and is stopped by
the groove, it is positioned exactly centrally with respect to the tube length. The same considerations apply to the
Markes Unity thermal desorber.

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Once capped, the Turbomatrix steel tube has to be positioned in the carousel with the grooves on the bottom.
The described conditions have been optimized for seven days exposures to typical concentrations of urban atmo-
spheres and indoor environments. Shorter exposure times or considerably higher concentrations would require dif-
ferent settings of split flows.

Temperatures and timing

• Desorption: 350 °C for 6 minutes, nitrogen flow through the tube 100 ml·min-1, of which 20 ml·min-1 sent to
the cryofocalization trap and 80 ml·min-1 to the inlet split:
• Cryofocusing trap (Tenax TA): adsorption -20 °C, desorption 99 °C·sec-1 up to 290 °C, 1 minute at 290 °C,
trap desorption in nitrogen flow at 26.8 ml·min-1, of which 25 ml·min-1 at the split outlet;
• Six port valve: 150 °C
• Transfer line: 200 °C

Instrumental analysis
Column
J&W GS-GASPRO, length 60 m, i.d. 0.32 mm; the column is directly fitted to the six-port valve of Turbomatrix appa-
ratus.

Temperatures
• GC oven: 80 °C for 1 minute, 25 °C·min-1 up to 175 °C, mantain for 8 minutes, 25 °C·min-1 up to 250 °C, final
isotherm 11.2 minutes
• Interface GC-MS: 290 °C
• Ionic source: 230 °C, quadrupole 150 °C

Flows
• Carrier gas: helium at 1.8 ml·min-1

Calibration
The calibration curve is performed by injecting known aliquots of a gaseous mix-
ture certified as 1,3-butadiene in nitrogen onto virgin cartridges. The operation is
carried out with the injector of a gas chromatograph whose output is grafted with
a short piece (10 cm) of a deactivated capillary column (0.25 mm id) connected
to a Swagelock reducer 1/16 "-1/4" .
Instead of the 1/4 ”steel ferrule of the reducer, one of those in PTFE used for clo-
sing the Turbomatrix tubes is used
Introduced a virgin cartridge in the Turbomatrix tube and inserted the tube in the Swagelock reducer, keeping the
injector at 50 °C and the oven cold, injecting different volumes of the gas mixture under a flow of nitrogen of 30
ml·min-1, leaving flow the gas for 2 minutes.
It is recommended to use a mixture of 1,000 ppm of 1,3-butadiene in nitrogen and to inject aliquots of 20, 40, 60,
80 and 100 µl of mixture (with a 100 µl gas-tight syringe) or 100 aliquots , 200, 300, 400 and 500 µl of mixture (with
a 500 µl gas-tight syringe) according to the desired calibration range.

Cartridges conditioning
The cartridges can be reconditioned using the thermal desorber in "tube conditioning" mode, heating them to 350
°C for at least 20 minutes in an inert gas flow (helium or nitrogen at a flow of 50 ÷ 100 ml·min-1).

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Index by code

Code Description Pag.

RAD120 white diffusive body A5, A8
RAD1201 blue diffusive body A5, A8
RAD1202 yellow diffusive body A5
RAD1203 permeative diffusive body, silicone membrane A5
RAD121 supporting plate A5, A8
RAD122 vertical adapter B1
RAD1221 vertical snapping adapter A8
RAD123- radiello-ready-to-use A8
RAD1241 polycarbonate caps A8
RAD1241 polypropylene containers for radiello-ready-to-use A8
RAD125 anaesthetic gases and vapors - sampling kit L1
RAD126 thermometer and data logger B3
RAD127 temperature reader with serial port adapter and software B3
RAD130 volatile organic compounds (VOCs) - CS2 desorbed D1
RAD132 anaesthetic gases and vapours - adsorbing cartridge L1
RAD141 1,3-butadiene and isoprene N1
RAD145 volatile organic compounds (VOCs) - thermally desorbed E1
RAD147 phenol, methylphenol and dimethylphenol M1
RAD165 aldehydes C1
RAD166 NO2 and SO2 F1
RAD168 NH3 I1
RAD169 HCl J1
RAD170 H 2S H1
RAD171 calibration solution for H2S B4, H2
RAD172 O3 G1
RAD175 stainless steel net (100 mesh, 5.9 mm diameter) empty cartridge B6
RAD176 stainless steel net (100 mesh, 4.9 mm diameter) empty cartridge B6
RAD177 stainless steel net (3x8 µm, 4.9 mm diameter) empty cartridge B6
RAD190 self-adhesive barcode label A5, B6
RAD195 clip B6
RAD196 protective shelter B1
RAD198 plastic strip B2, B6
RAD1991 empty glass tube and cap B6
RAD1992 empty plastic tube and cap B6
RAD302 calibration solution for aldehydes B4, C3
RAD405 calibration kit for BTEX, CS2 desorbed B5
RAD406 calibration kit for COV, workplace environment B5
RAD407 calibration kit for BTEX, thermally desorbed B5

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