This document specifies a method for the determination of organic isocyanates in workplace air using derivatization with di-n-butylamine (DBA) and chromatographic analysis.

This document is applicable to the determination of a wide range of organic isocyanates present in both the gas phase and the particle phase in workplace atmospheres, including monofunctional isocyanates such as isocyanic acid (ICA), methyl isocyanate (MIC), ethyl isocyanate (EIC), propyl isocyanate (PIC), butyl isocyanate (BIC) and phenyl isocyanate (PhI); monomeric diisocyanates, including 1,6-hexamethylene diisocyanate (HDI), 2,4- and 2,6-toluene diisocyanate (TDI), 4,4′-methylenediphenyl diisocyanate (MDI), 1,5-naphthyl diisocyanate (NDI), isophorone diisocyanate (IPDI) and 4,4′-dicyclohexylmethane diisocyanate (H12MDI); and multifunctional isocyanates, including oligomeric, prepolymeric and polymeric forms such as biuret-, isocyanurate- and allophanate-adducts.

The method covers air sampling using impingers, filters or combinations thereof, and analysis by liquid chromatography with mass spectrometric detection.

The useful analytical range is approximately 2,5 ng to 500 ng of isocyanate per sample. For a nominal air sample volume of 15 l, this corresponds to approximately 0,2 µg/m³ to 33 µg/m³. These values can vary depending on the isocyanate analysed.

This document does not apply to the determination of amines or aminoisocyanates. For the determination of amines and aminoisocyanates, the method specified in ISO 17734-2[11].