Figure 2

Elimination kinetics for isocyanate-diamines: 1,6-HDA (A), 2,4-TDA (B), 2,6-TDA (C), 4,4'-MDA (D), sum of the cis- and trans-IPDA isomers (E) and 1,5-NDA (F) in urine of patients after inhalation challenge with either 1,6 -HDI (n = 55), 2,4-TDI (n = 18), 2,6-TDI (n = 18), 4,4'-MDI (n = 36), IPDI (n = 9) or 1,5-NDI (n = 3), respectively. Spot urine samples were voided by the patients at various time points (the collection times are shown on the × axis) after the controlled exposure (0-24 h). The data points on the Y axis represent median diamine values (expressed as μg/g creatinine) with standard deviations for the patient samples detected with mass spectrometry (analysed against analytical standards for each individual diamine). The trend curves are shown for the low, 496 ± 103 ppb-min (blue, L) as well as high, 1560 ± 420 ppb-min (red, H) exposure groups (see additional files 1, 2, 3 and 4 for details on patient exposure and sampling). The geometric mean was calculated for the cumulative values from all patients to estimate the excretion time points for each individual isocyanate and to calculate the overall trend patterns (black lines).