Figure 1

The GC-MS analysis of isocyanate diamine-metabolites. Urine samples were subjected to strong acid hydrolysis, separated with gas chromatography (GC) and the individual isocyanate diamines were detected with mass spectrometry (MS), as described in methods. Data show the individual retention time (RT) points (after the GC column separation) and their respective mass/charge (m/z) data (MS detector) with the individual target und qualifier ions allowing to recognize the following metabolites: 1,6 HDA (used to detect 1,6-HDI exposure), 2,4-TDA, 2,6-TDA (to detect 2,4 and 2,6-TDI exposure), cis- and trans- IPDA (to detect exposure to isophorone diisocyanates), 1,5-NDA, (to detect exposure to 1,5 NDI), 4,4'-MDA (to detect exposure to 4,4'-MDI). Additionally, 1,7-HeDA and 3,3'-MDA were used as internal control standards.