Biomarkers in hydrolysed urine, plasma and erythrocytes among workers exposed to thermal degradation products from toluene diisocyanate foam.
ABSTRACT Blood and urine samples were collected from six workers and two volunteers exposed to thermal degradation products from toluene diisocyanate (TDI)-based polyurethane (PUR) before and during the summer vacation. Air samples were collected on filters impregnated with 9-(N-methylaminomethyl)anthracene. The concentrations of the amines corresponding to 2,4- and 2,6-TDI, i.e., 2,4- and 2,6-toluenediamine (TDA), were determined in urine (U-TDA), plasma (P-TDA) and erythrocytes (E-TDA) after acid hydrolysis as pentafluoropropionic anhydride derivatives by GC-MS. Among the workers urinary elimination phases were seen. The estimated medians of the urinary half-lives were for the slow phase 18 d for 2,4-TDA and 19 d for 2,6-TDA. P-2,4-TDA ranged between 2.5 and 19 ng ml-1 and P-2,6-TDA between 4.4 and 30 ng ml-1. The estimated median of the half-lives in plasma were 7.8 d for 2,4-TDA and 9.6 d for 2,6-TDA. E-2,4-TDA ranged between 0.5 and 6.6 ng g-1 and E-2,6-TDA between 1.2 and 14 ng g-1. A significant linear relationship was found between the mean P-TDA and the mean E-TDA. Linear relationships were observed between the mean daily U-TDA and P-TDA and E-TDA. Virtually linear relationships were obtained for P-TDA and E-TDA and the TDI air levels. Proteins from lysed erythrocytes were separated and fractionated by gel filtration. 'TDI'-modified proteins were found in six out of a total of 80 fractions (fractions 51-56). These co-eluted completely with the haemoglobin (UV, 415 nm). Fractions 51-56 contained 89% of the applied amounts of 2,4-TDA and 81% of 2,6-TDA.
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ABSTRACT: A methodology for workplace air monitoring of aromatic and aliphatic, mono- and polyisocyanates by derivatisation with di-n-butylamine (DBA) is presented. Air sampling was performed using midget impinger flasks containing 10 ml of 0.01 mol l−1 DBA in toluene and a glass-fibre filter in series after the impinger flask, thereby providing the possibility of collecting and derivatising isocyanates in both the gas and particle phases. Quantification was made by LC-MS, monitoring the molecular ions [MH]+. Air samples taken with this method in car repair shops showed that many different isocyanates are formed during thermal decomposition of polyurethane (PUR) coatings. In addition to isocyanates such as hexamethylene (HDI), isophorone (IPDI), toluene (TDI) and methylenediphenyl diisocyanate (MDI), monoisocyanates such as methyl (MIC), ethyl (EIC), propyl (PIC), butyl (BIC) and phenyl isocyanate (PhI) were found. In many air samples the aliphatic monoisocyanates dominated. During cutting and welding operations, the highest levels of isocyanates were observed. In a single air sample from a welding operation in a car repair shop, the highest concentrations found were: MIC, 290; EIC, 60; PIC, 20; BIC, 9; PhI, 27; HDI, 105; IPDI, 39; MDI, 4; and 2,4-TDI and 2,6-TDI 140 µg m−3. Monitoring the particle size distribution and concentration during grinding, welding and cutting operations showed that ultrafine particles (<0.1 µm) were formed at high concentrations. Isocyanates with low volatility were mainly found in the particle phase, but isocyanates with a relatively high volatility such as TDI, were found in both the particle and gas phases.Journal of Environmental Monitoring 01/2000; 2(5):462-469. · 2.09 Impact Factor
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ABSTRACT: Toluene diisocyanate (TDI) air levels were studied at two TDI-polyurethane (TDI-PUR) factories. One plant was manufacturing TDI-PUR foam and the other produced flame laminated textiles. Sampling was performed with impinger flasks containing 9-N-methyl-aminomethyl-anthracene in toluene as the isocyanate-derivatization reagent, followed by LC-UV, and impinger flasks containing di-n-butylamine (DBA) in toluene as the isocyanate-derivatisation reagent, followed by the derivatisation of amines with ethylchloroformate and determination using LC-UV-MS. The assessment of isocyanates in air using conventional LC-methods, involves a risk for underestimation of the air concentrations. Structural information about isocyanates and amines were obtained using the DBA-method with MS. In the samples, isocyanate concentrations up to 57 mg m−3 of TDI were observed. TDA was found in air at concentrations up to 70 mg m−3. The data of the high air concentrations observed at the two PUR-factories in this study is not part of an exposure assessment but they greatly stress the need to use fail-safe work environment hygiene.Journal of Liquid Chromatography & Related Technologies 08/2006; 20(14):2207-2219. · 0.57 Impact Factor