The following sampling system is available at the GSA for the sampling of isocyanates:

  • SG5100ex with a cartridge (stationary and personal sampling).   

The air loaded with organic compounds is sucked in with a battery-operated and volume flow-controlled pump (SG5100ex) with a volume flow of 1 l/min. We recommend a measuring period of 2 h. Through the cartridge, the organic compounds are sucked out of the air and adsorbed. 

A glass fibre filter impregnated with 1-(2-methoxyphenyl) piperazine with a diameter of 25 mm is used as the filter medium.



The derivatised isocyanates are desorbed by extraction of the filter with acetonitrile in an ultrasonic bath and then analysed by HPLC (high performance liquid chromatography) and UV detection (photo diode array detector).


Limit value

Occupational limit values according to TRGS 900 (March 2021):

Substance Occupational exposure limit [mg / m³]
1,6-Hexamethylene diisocyanate (HDI) 0.035
2,2-Toluylene diisocyanate (4-methyl-m-phenylene diisocyanate) 0.035
2,6-Toluylene diisocyanate (2-methyl-m-phenylene diisocyanate) 0.035
Diphenylmethane-4,4‘-diisocyanate (4,4′-methylene diphenyl diisocyanate) 0.05 E


Stationary measurement of isocyanates
Stationary measurement of isocyanates