title: Dry sampling of gas-phase isocyanates and isocyanate aerosols from thermal degradation of polyurethane.
abstract: The performance of a dry sampler, with an impregnated denuder in series with a glass fibre filter, using di-n-butylamine (DBA) for airborne isocyanates (200ml min(-1)) is investigated and compared with an impinger flask with a glass fibre filter in series (1 l min(-1)). An exposure chamber containing 1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), and 2,4- and 2,6-toluene diisocyanate (TDI) in the concentration range of 5-205 μg m(-3) [0.7-33 p.p.b.; relative humidity (RH) 50%], generated by gas- and liquid-phase permeation, was used for the investigation. The precision for the dry sampling for five series with eight samplers were in the range of 2.0-6.1% with an average of 3.8%. During 120-min sampling (n = 4), no breakthrough was observed when analysing samplers in series. Sixty-four exposed samplers were analysed after storage for 0, 7, 14, and 21 days. No breakdown of isocyanate derivatives was observed. Twenty-eight samplers in groups of eight were collecting isocyanates during 0.5-32h. Virtually linear relationships were obtained with regard to sampling time and collected isocyanates with correlation coefficients in the range of 0.998-0.999 with the intercept close to the origin. Pre- or post-exposure to ambient air did not affect the result. Dry sampling (n = 48) with impinger-filter sampling (n = 48) of thermal decomposition product of polyurethane polymers, at RH 20, 40, 60, and 90%, was compared for 11 isocyanate compounds. The ratio between the different isocyanates collected with dry samplers and impinger-filter samplers was in the range of 0.80-1.14 for RH = 20%, 0.8-1.25 for RH = 40%, 0.76-1.4 for RH = 60%, and 0.72-3.7 for RH = 90%. Taking into account experimental errors, it seems clear that isocyanic acid DBA derivatives are found at higher levels in the dry samples compared with impinger-filter samplers at elevated humidity. The dry sampling using DBA as the reagent enables easy and robust sampling without the need of field extraction.
authors: Work Environment Chemistry, Stockholm University, PO Box 460, 281 24 Hässleholm, Sweden;
authors: Daniel
authors: D
authors: Gylestam
authors: Jakob B
authors: JB
authors: Riddar
authors: Daniel
authors: D
authors: Karlsson
authors: Jakob
authors: J
authors: Dahlin
authors: Marianne
authors: M
authors: Dalene
authors: Gunnar
authors: G
authors: Skarping
mesh_terms: D000336:Aerosols / Q000032:analysis; D000395:Air Pollutants, Occupational / Q000032:analysis*; D002853:Chromatography, Liquid; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D006801:Humans; D017953:Isocyanates / Q000032:analysis*; D016273:Occupational Exposure / Q000032:analysis; D053719:Tandem Mass Spectrometry; D013997:Time Factors
chemical_list: D000336:Aerosols; D000395:Air Pollutants, Occupational; D017953:Isocyanates
keywords: airborne isocyanates; dibutylamine derivatives; dry sampling; liquid chromatography–mass spectrometry; thermal decomposition