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0.2 0.5 1.0 PPM N 5: (Last Updated: - 2023)

The document provides specifications for a formaldehyde detector tube (No. 91L) with a measuring range of 0.1 to 5.0 ppm and a detection limit of 0.05 ppm. It includes details on performance, operating conditions, possible interferences, and other substances that can be measured with the tube. The shelf life is 36 months when stored in a refrigerator.

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Mohammadali Nasiroleslami
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11 views1 page

0.2 0.5 1.0 PPM N 5: (Last Updated: - 2023)

The document provides specifications for a formaldehyde detector tube (No. 91L) with a measuring range of 0.1 to 5.0 ppm and a detection limit of 0.05 ppm. It includes details on performance, operating conditions, possible interferences, and other substances that can be measured with the tube. The shelf life is 36 months when stored in a refrigerator.

Uploaded by

Mohammadali Nasiroleslami
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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Formaldehyde HCHO No.

91L

n=5
ppm
Scale

91L
0.2
0.5
1.0

2.0
3.0
4.0
5.0
Performance The minimum scale value (0.1ppm) is not printed on the tube, but only the scale line is printed.
Measuring range （0.1）to 5.0 ppm 5.0 to 45.0 ppm
Number of pump strokes 5（500 mL） 1（100 mL）
Correction factor 1 9
Sampling time 7.5 min 1.5 min
Detecting limit : 0.05 ppm（5 pump strokes）
Colour change : Yellow → Reddish brown
Operating conditions : Temperature 0 to 40 ℃ (32 to 104 ℉) correction used
Relative humidity 0 to 90 % correction not used
Relative standard deviation : 10 %（for 0.1 to 0.5 ppm）, 5 %（for 0.5 to 5 ppm）
Tube quantity and number of tests per box : 10 tubes for 10 tests
Shelf life : 36 months（in the refrigerator）

Reaction principle
3HCHO ＋（NH2OH）3H3PO4 → H3PO4
H3PO4 ＋ Base → Phosphate

Possible coexisting substances and their interferences


Substance Concentration Interference Changes colour by itself to
Aldehydes, Ketones ＋ Reddish brown
Acid gases ＋ Red
Organic acids No No

Other substances measurable with this detector tube


Substance Correction No. of pump strokes Measuring range
Benzaldehyde by scale 1 4 to 92 ppm
Cyclohexanone by scale 1/2 10 to 470 ppm
Diisobutyl ketone Factor : 5.8 4 0.58 to 29 ppm
Metaldehyde Factor : 0.65 3 0.065 to 3.25 ppm
Propionaldehyde Factor : 7.6 1 0.76 to 38 ppm

Calibration gas generation


Diffusion tube method

(Last updated: Jul. 2023)

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