Determination of Toluene Diisocyanate in Air Using DI-n-Butylamine and 9-N-Methyl-Aminomethyl-Anthracene as Derivatization Reagents

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.