ESTERS 1 1450

Formulas: Table 1 MW: Table 1 CAS: Table 1 RTECS: Table 1

METHOD: 1450, Issue 3 EVALUATION: FULL Issue 1: 15 February 1984

Issue 3: 15 March 2003

OSHA : Table 1 PROPERTIES: Table 1

NIOSH: Table 1
ACGIH: Table 1

COMPOUNDS: n-amyl acetate 1-butyl acetate isobutyl acetate ethyl acrylate

2-ethoxyethyl acetate methyl isoamyl acetate n-butyl acetate
n-propyl acetate sec-butyl acetate isoamyl acetate

SYNONYMS: See Table 1

SAMPLING MEASUREMENT

SAMPLER: SOLID SORBENT TUBE TECHNIQUE: GAS CHROMATOGRAPHY, FID

(coconut shell charcoal, 100 mg/50 mg)
ANALYTE: Compounds referenced above
FLOW RATE: 0.01 to 0.2 L/min
DESORPTION: 1 mL CS2 , 30 min
VOL-MIN: 1 L @ OSHA PEL
-MAX: 10 L INJECTION
VOLUME: 1 µL
SHIPMENT: Refrigerated
TEMPERATURE
SAMPLE -INJECTION: 200 - 225 °C
STABILITY: See EVALUATION OF METHOD -DETECTOR: 250 - 300 °C
-COLUMN: 50 °C for 2 minutes, then up to 110
BLANKS: 2 to 10 field blanks per set °C at a rate of 5 °C per minute,
holding at 110 °C for 3 minutes.

ACCURACY CARRIER GAS: 4 mL/min, Helium

RANGE STUDIED: 0.5 to 2x OSHA PEL[1] COLUMN: Capillary, fused silica, 30m x 0.32-
mm ID; 0.5 µm film DB-Wax or
equivalent.
ACCURACY: See EVALUATION OF METHOD
CALIBRATION: Solutions of compounds in CS2
BIAS: See EVALUATION OF METHOD
RANGE: See EVALUATION OF METHOD
OVERALL
and Table 1.
PRECISION ( Ö r T ): See EVALUATION OF METHOD
LOD: See EVALUATION OF METHOD

PRECISION ( Ö r ): See EVALUATION OF METHOD [1]

APPLICABILITY: This method can be used for simultaneous analysis of all analytes. High humidity greatly reduces sampler
capacity and breakthrough volume.

INTERFERENCES: None identified.

OTHER METHODS: This method, NMAM 1450, Issue 3 is an updated analytical procedure [5]. This method originally
combined and replaced the NMAM 2nd edition Methods S31, S32, S35, S37, S41, S44 through S48, and S51 [3]. Estimated
LOD for each analyte is approximately 10 times lower than that of the previous methods.

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REAGENTS: EQUIPMENT:

1. Desorbing solution: Carbon disulfide* 1. S am pler: glass tube, 7-cm long, 6-mm OD, 4-
(chromatographic grade) with 0.05% (v/v) n- m m ID, flame-sealed ends, containing two
hexane or other suitable internal standard. sections of activated (600 °C) coconut s hell
2. Analyte, reagent grade. charcoal (front - 100 mg; back - 50 mg)
3. Helium, purified. separated by a 2-m m ureth ane foam plug. A
4. Hydrogen, prepurified. silylated glass wool plug precedes the front
5. Air, compressed, filtered. section and a 3-m m urethane foam plug follows
the back section. Pressure drop across the tube
* See SPECIAL PRECAUTIONS at 1 L/m in airflow must be less than 3.4 kPa.
Tubes are comm ercially available.
2. Personal sampling pump, 0.01 to 0.2 L /m in, with
flexible connecting tubing.
3. Refrigerant, bagged (“Blue Ice,” or equivalent).
4. Gas chromatograph, FID, integrator and column
(page 145 0-1).
5. Vials, glass, 2-mL, PTFE -lined crimp caps.
6. Syringe, 10-µL, readable to 0.1 µL, 25-, 50- and
100-µL.
7. Volumetric flasks, 10-mL.
8. Pip et, volumetric, 1-mL, with pipet bulb or
repipet.

SPE CIAL PR ECAU TIO NS: Carbon disulfide is toxic and an acute fire and explosion hazard (flash point
= -30 °C); work with it only in a hood. W ear appropriate protective clothing and gloves.

SAMPLING:

1. Calibrate each personal sampling pump with a representative sampler tube in line.
2. Break the ends of the sampler tube immediately before sampling. Attach sampler tube to personal
sampling pump with flexible tubing.
3. Sa m ple at an accurately known flow rate between 0.01 and 0.2 L/min for a total sam ple size of 1 to 10 L.
4. Cap the sam plers with plastic (not rubber) caps and pack securely for shipm ent w ith bag ged refrige rant.

SAMPLE PREPARATION:

5. Place the front and back sorbent sections of the sampler tube in separate vials. Discard the glass wool
and foam plugs.
6. Ad d 1.0 m L desorbing solution to each vial. Attac h crim p cap to each vial.
7. Allow to stand 30 min with occasional agitation.
NOTE: The desorption efficiency of 2-ethoxyethyl acetate has been found to decrease with the resident
tim e of the des orbe d so lution with charcoal [4]. After 30 min desorption transfer the supernatant
solution of 2-ethoxyethyl acetate to a clean 2-mL vial and seal with a crimp cap.

CALIBRATION AND QUALITY CONTRO L:

8. Calibrate daily with at least six working standards over the range 0.001 to 10 mg analyte per sample.
a. Add k now n am ounts of analyte to desorbing solution in 10-mL volumetric flasks and dilute to the
m ark .
b. Analyze together with samp les and blanks (steps 11 and 12).
c. Prepare calibration graph (ratio of peak area of ana lyte to pea k area o f internal stan dard vs.m g
analyte).

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9. Determine desorption efficiency (DE) at least once for each lot of charcoal used for sampling in the
calibration range (step 8). Prepare three tubes at each of five concentrations plus three media blanks.
a. Rem ove and disca rd back sorbent sec tion of a blank sam pler.
b. Inject a known amount of analyte directly onto front sorbent section with a microliter syringe.
c. Ca p the tube. Allow to stand overnight.
d. Deso rb (steps 5 through 7 ) and analyze together with working standards (steps 11 and 12).
e. Prepare a graph of DE vs. mg analyte recovered.
10. Analyze three quality control blind spikes and three ana lyst spikes to insure that the calibration graph and
DE graph are in control.

MEASUREMENT:

11. Set gas chrom ato graph acc ording to m anufacturer’s recomm endations and to conditions given on page
145 0-1. Inject sam ple aliqu ot with a utos am pler, or m anu ally using solve nt flush technique.
NOTE: If peak area is above the linear range of the working standards, dilute with desorbing solution,
reanalyze, and apply the appropriate dilution factor in calculations.
12. Mea sure pea k area. Divide the peak area of analyte by the peak area of internal standard on the same
chromatogram.

CALCULATIONS:

13. De termine the m ass , (:g, corrected for DE ) of analyte found in the samp le front (W f) and back (W b)
sorbent sec tions and in the average m edia blank front (B f) and back (B b) sorben t sec tions.
NO TE: If W b > W f/10, report breakthrough and possible sample loss.
14. Calculate conce ntration, C, of analyte in the air volume sam pled, V (L):

EVALUATION OF METHOD:

Previous Evaluation

The original methods for S31 (sec-amylacetate), S47 (n-butyl acetate), S46 (sec-butyla cetate ), S32 (t-b utyl
acetate), S41 (2 -etho xy acetate ), S35 (ethyl acrylate), S45 (iso am yl aceta te), S4 4 (is obutyl ace tate), S 37
(m eth yl isoamyl acetate), S48 (n-propyl acetate) were issued on December 6, 1974, ex cept for S51 (n -am yl
acetate), which was issued on January 17, 1975 [3]. Atmospheres of each compound were generated in dry
air by calibrated syringe drive and 10-L air samples were taken [1]. Collection efficiency in humid air and
sample storage stability were not tested. Spiked samplers were used to study measurement precision and
des orption efficienc y (DE).

Current Evaluation

Methods for esters (n-amyl acetate, n-butyl acetate, sec-butyl acetate, t-butyl acetate , 2-eth oxyeth yl acetate,
eth yl acrylate, isoamyl acetate, isobutyl aceta te, m eth yl isoam yl acetate, n-propyl acetate) were evaluated [5]
using analytes fortified on Anasorb CSC sorbent tubes (Lot #2000). Desorption efficiency (DE) and precision
are shown in Table 2. Sec -am yl aceta te was evaluated in the previous issue of this method but it was not
includ ed in th is current update.

Storage stability studies were performed on Anasorb C SC tubes (Lo t #2000) at approxim ate ly 150 µg each
analyte/sample. The s am ples were stored for up to 30 days at 4 °C. T he recove ries of 30-day storage are
summ arized in Table 2.

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REFERENCES:

[1] NIOSH [1977]. Docum entation of the NIOSH Validation Tests. U.S. Department of Health, Education
and W elfare, Publ. (NIOSH) 77-185.
[2] UTBL [1983]. UTBL user check, NIOSH Sequence #4121-N (unpublished), November 15.
[3] NIO SH [1977]. NIO SH Ma nua l of Analytical Metho ds, 2 nd ed., V.2., U.S. Department of Health,
Education and Welfare, Publ. (NIOSH) 77-157-B.
[4] Corelson D [1988]. Menlo Park, CA., SRI. Personal communication with NIOSH.
[5] Yoon YH, Perkins JB, Reynolds JM [2002]. Back-up Data Report for Esters 1, DataChem
Laboratories, Inc. under NIOSH contracts CDC-200-95-2955 and CDC 200-2001-08000.

PRE VIOU S RE VISION BY :

Robert W . Kurimo, NIOSH/DPSE ; methods originally validated under NIOSH C ontract CDC 99-74-45.

METHOD REVISED BY:

Young H ee Yoon, Ph .D., Ja m es B. P erkin s and John M. Reynolds, D ata Chem Laboratories, Inc ., Salt
Lake City, Utah.

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Table 1. General Information

VP @ 20 °C, Liquid Density,
Compound, Formula and RTECS Synonyms M.W. OSHA/NIOSH/ACGIH, ppm BP, °C kPa (mm Hg) g/mL @ 20 °C
n-amyl acetate acetic acid 1-pentanol ester; 130.18 TWA (STEL) 149 0.5(4) 0.876
CH3 COO(CH2 )4 CH3 ; C7 H1 4 O2 CAS #628-63-7 100/100/100
AJ1925000
sec-amyl acetate acetic acid 2-pentanol ester; 130.18 125/125/125 134 0.9(7) 0.866
CH3 COOCHCH3 (CH2 )2 CH3 ; C7 H1 4 O2 CAS #626-38-0
AJ2100000
n-butyl acetate acetic acid butyl ester; 116.16 150/150(200)/150(200) 126 1.3(10) 0.883
CH3 COO(CH2 )3 CH3 ; C6 H1 2 O2 CAS #123-86-4
AF7350000
sec-butyl acetate acetic acid 1-methyl propyl ester; 116.16 200/200/200 112 1.3(10) 0.865
CH3 COOCH(CH3 )CH2 CH3 ; C6 H1 2 O2 CAS #105-46-4
AF7380000
t-butyl acetate acetic acid 1, 1-dimethylethyl 116.16 200/200/200 98 not available 0.867
CH3 COOC(CH3 )3 ; C6 H1 2 O2 ester;
AF7400000 CAS #540-88-5
2-ethoxyethyl acetate Cellosolve acetate; acetic acid 132.16 100a /0.5a /5a 156 0.3(2) 0.973
CH3 COO(CH2 )2 OCH2 CH3 ; C6 H1 2 O3 ethylene glycol monoethyl ether
KK8225000 ester; CAS #111-15-9
ethyl acrylate 2-propenoic acid ethyl ester; 100.11 25a /4 LOQb /5a b (15 ppm) 99 3.9(30) 0.923
CH2 =CHCOOCH2 CH3 ; C5 H8 O2 CAS #140-88-5
AT0700000
isoamyl acetate acetic acid 3-methyl-1-butanol 130.18 100/100/100 142 0.5(4) 0.876
CH3 COO(CH2 )2 CH(CH3 )2 ; C7 H1 4 O2 ester;
NS9800000 CAS #123-92-2
isobutyl acetate acetic acid isobutyl ester; 116.16 150/150/150 117 1.7(13) 0.871
CH3 COOCH2 CH(CH3 )2 ; C6 H1 2 O2 CAS #110-19-0
AI4025000
methyl isoamyl acetate acetic acid 4-methyl-2-pentanol 144.22 50/50/50 146 0.5(3.8) 0.858
CH3 COOCH(CH3 )CH2 CH(CH3 )2 ; C8 H1 6 O2 ester; 1,3-dimethyl butyl acetate;
SA7525000 “sec-hexyl acetate;” CAS #108-
84-9
n-propyl acetate acetic acid n-propyl ester; 102.13 200/200 (250)/200 (250) 102 3.3(25) 0.890
CH2 COO(CH2 )2 CH3 ; C5 H1 0 O2 CAS #109-60-4
AJ3675000

a
Skin
b
Carcinogen

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Table 2. Current Method Evaluation

Overall Method Analytical Method Storage Stability Study

Measurement
Range Accuracy Breakthrough1 Bias S RT Range Studied LOD Average Precision Levels Recovery
Compound (mg/m3 ) at 2 x OSHA (%) (µg/sample) (µg/sample) DE (Ö r ) (µg/sample) (%)
PEL (# )

n-amyl acetate 208-871 0.163 34.2 L 0.3 0.0831 14-440 0.9 0.96 0.0072 140 98

n-butyl acetate 352-1475 0.136 20.5 L 0.3 0.0691 15-440 0.9 0.96 0.0087 140 98

sec-butyl acetate 478-2005 0.116 16.5 L -2.4 0.0539 14-440 0.9 0.97 0.0062 140 98

t-butyl acetate 424-1780 0.234 14.3 L -8.6 0.0897 14-430 0.9 0.98 0.0052 140 98

2-ethoxyethyl acetate 262-1100 0.203 34.6 L -9.6 0.0648 16-340 1 0.82 0.020 160 96

ethyl acrylate 50-210 0.162 >45 L -7.1 0.0550 31-300 2 0.86 0.015 150 90

isoamyl acetate 208-874 0.195 32.3 L -7.1 0.0750 14-430 0.9 0.97 0.0066 140 98

isobutyl acetate 306-1280 0.133 21.5 L 1.8 0.0656 14-440 0.9 0.97 0.0084 140 98

methyl isoamyl acetate 143-601 0.126 >45 L -2.6 0.0590 14-280 0.9 0.81 0.015 140 95

n-propyl acetate 384-1610 0.162 17.9 L 6.9 0.0566 15-450 0.9 0.95 0.0091 140 98

1
The values for these categories were taken from the original methods validation, see ref [1].

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition