A novel analytical method for simple and low-cost detection of isocyanates in ambient air

In this study, we developed a novel method for the collection of gaseous and particulate isocyanates in the air using di-n-butylamine (DBA)-coated glass fiber filters and a cation-exchange column (GFF_SCX-DBA) sampler. Our method showed acceptable linearity, accuracy, and precision in the analysis of eleven kinds of isocyanates (ICA, MIC, EIC, PIC, PHI, 1,6-HDI, 2,4-TDI, 2,6-TDI, trans-IPDI, cis-IPDI, and 4,4'-MDI). And, some of them were detected in the air at the plant manufacturing isocyanates and spray polyurethane foam. Actually, 2,4-TDI and 2,6-TDI (11,000 ± 6600 and 5800 ± 3500 ng/m³, respectively) were detected at much higher levels than others at the plant manufacturing isocyanates, and the levels of these isocyanates were comparable with those obtained by using the commercial sampler. Furthermore, PHI and 4,4'-MDI (5800 ± 470 and 3500 ± 1100 ng/m³, respectively) were detected at a relatively higher concentration than the others in the place of spray polyurethane foam. Through this study, we realized that the concentration of isocyanates in various working places could be analyzed using our GFF_SCX-DBA sampler. This method makes it possible to perform a rapid and simplified extraction operation in a shorter time than in the commercial sampler by combining the GFF and SCX samplers.