GAS3D Ammonia Passive Dosi-Tube 2.5 – 1000ppm

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GAS3D Ammonia (NH3) Gastec Passive Sampling Dosi Tubes (Time Weighted Average Detector Tubes)

The Dosi-Tube System allows an operator to evaluate the level of gas a worker is exposed to over a time period such as a working shift.

The Dosi-Tube is easily clipped into the Dosi-tube holder (GAS710) which is worn on a garment of clothing.

Measuring Range 2.5 to 1000ppm
Sampling Hours 0.5 to 10 hours
Detecting Limit 0.5ppm (10 hours)
Colour Change Purple       Yellow
Reaction Principle Ammonia neutralizes analyzing agent to discolour the indicator to yellow.
Coefficient of Variation 10% (for 25 to 500 ppm・hr)
Shelf Life Up to 3 years from point of manufacture
Corrections for
temperature & humidity
Temperature correction is necessary
Store the tubes at cool and dark place.


Possible coexisting substances and their interferences
Substance Concentration Interference Change colour by itself
Amines, Hydrazine Plus error Produce yellow stain.
Aromatic amines No effect No discoloration
Other substance measurable with this detector tube
Substance Correction Factor Sampling Time Measuring Range
Dimethylamine 0.75 0.5 to 10 hours 1.9 to 750 ppm
N,N-Dimethylethylamine 1.6 4 to 1600 ppm
Hydrazine 0.65 1.6 to 650 ppm
Triethylamine 2.1 5.3 to 2100 ppm
Calibration gas generation Permeation tube method

Additional Information

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