Monitoring of isocyanates in the workplace environment is important as these reactive compounds are capable of inducing respiratory disorders like “occupational asthma”. Airborne monomer and oligomer isocyanates can occur together in product formulations, such as automotive clear coat finishes. Analyzing the monomer and oligomer isocyanates in a single method provides the most efficient solution for determining the concentrations present during potential exposures. In a comparative study, air samples generated from spray painting were collected using two variations of “dry” sampling devices. These sampling devices incorporated either dibutylamine(DBA) or 1-(2-pyridyl)piperazine(1-2pp) impregnated media to create stable target derivatives. The resulting derivates were then analyzed by sampler specific HPLC finishes. Quantitation of detected monomeric and oligomeric isocyanates using LC-MS-MS was possible by using available deuterated internal standards. Both monomers and oligomers of isophorone diisocyanate (IPDI), and 1,6-hexamethylene diisocyanate (HDI) were detected. Other oligomeric species were also detected but at lower concentrations. The results showed that the oligomers of HDI-Isocyanurate and IPDI-Isocyanurate were present at the highest concentration inside the spray booth during the spraying process indicating that oligomers can be present at much higher concentrations than the monomers during the spray painting process.
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Gary is currently an R&D chemist in the Environmental Air Monitoring group at the Supelco division of Sigma Aldrich after working for six years as a technical service chemist. As an R&D chemist, he is involved with helping develop new products and testing methodologies in air monitoring. He previously has spent over twenty years in analytical chemistry involved with the identification of micro and macro contaminations in failure analysis, deformulation, forensic, and industrial hygiene sample testing.
