DAN is a novel derivatizing agent for isocyanate sampling which targets total reactive isocyanate group (TRIG). Field evaluations have been conducted for 4,4'-Methylene diphenyl diisocyanate (MDI) sampling using DAN as the derivatizing agent in a CIP10. The perimidone formed, selective of TRIG, was analyzed in laboratory by liquid chromatography coupled to tandem mass spectrometry. Workplaces using MDI-based polyurethane spray foam and MDI wood product binder were studied. Each study compared the data obtained between the CIP10/DAN, the CIP10/MP, and a reference method. As a first evaluation, the CIP10/DAN sampled simulated MDI spray foam atmosphere in parallel with impingers (reference method) and CIP10/MP. The mean of the TRIG concentration values measured was 16% (95% confidence interval [CI], [1, 31]) higher for the CIP10/MP samples as compared to the impinger samples, while the mean TRIG concentrations found were 98% (95% CI [63, 133]) higher for the CIP10/DAN samples as compared to the impinger samples. For sampling done in a real workplace using MDI-based spray foam, the CIP10/DAN method showed lower results than the CIP10/MP method. The presence of hygroscopic DMSO used in the DAN approach is a limitation and may prevent obtaining accurate results in the spray foam atmosphere. CIP10/DAN was also studied in MDI wood product binder atmosphere. Mean TRIG concentrations found were 80% (95% CI [51, 110]) and 79% (95% CI [50, 108]) lower for the CIP10/MP and CIP10/DAN method, respectively, as compared to the reference method (a 13-mm filter coated with MP). In this case, the CIP10 may have reached its limit in this last evaluation where vapors and particles below 1 µm were not collected as efficiently as they were with the reference method.
Keywords: 1,8-diaminonaphthalene; exposure assessment methodology; isocyanate; methylene diphenyl diisocyanate; perimidone.
© The Author 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.