Determination of complex mixtures of airborne isocyanates and amines. Part 2. Toluene diisocyanate and aminoisocyanate and toluenediamine after thermal degradation of a toluene diisocyanate–polyurethane

Abstract

An LC-MS method is presented for the determination of thermal decomposition products of polyurethane. The method is based on the collection of air samples in midget impinger flasks containing 0.01 moll-1 dibutylamine (DBA) dissolved in toluene. DBA reacts with isocyanates to give urea derivatives. The amines simultaneously collected were derivatized with ethyl chloroformate (ET) to give urethane derivatives. Two isomers of toluene diisocyanate (2,4-and 2,6-TDI), toluene-2,4-and -2,6-diamine (TDA), three isomers of toluene aminoisocyanates and oligomers with two and three aromatic rings were determined in air containing thermal decomposition products of TDI-polyurethane. LC with gradient elution, at 0.5 ml min-l starting with acetonitrile-water (46 + 54) and ending after 14 min with acetonitrile-water (77.5 + 22.5) and atmospheric pressure ionization monitoring of positive ions demonstrated highly sensitive and selective determinations. Quantification was performed by monitoring the molecular ion [M + 1]+ of TDI-DBA and TDA-ET derivatives. The instrumental detection limit was 1 nmol 1-1 of TDI-DBA and 2 nmol l-l of TDA-ET. Linear calibration curves were obtained and the correlation coefficient was 0.9981-0.9996 for 50-500 nmol 1-1 (n = 14). The over-all precision for samples spiked at a concentration of 500 nmol 1-l of 2,4and 2,6-TDA-ET and 2,4-and 2,6-TDI-DBA was 1.7, 1.6, 1.8 and 1.9% (n = l l ) , respectively.

Isocyanates, aminoisocyanates and amines from fires—a screening of common materials found in buildings

“…The production volume per year of materials where this substance is used is large and increasing. The issue of isocyanates has up to now mainly been focused on health related effects Contract grant/sponsor: Swedish Fire Research Board (BRANDFORSK); contract grant/number: 324-021 from emissions of these species in, for example, the production of PUR products [1,2], 'hot work' with cyanate based lacquers [3] and flame lamination of PUR with textiles [4].…”

Identification of the isocyanates generated during the thermal degradation of a polyurethane car paint

“…The typical polyurethane paint system has two components: polyol with pigments, solvents, and additives; and a second component containing the polymeric isocyanate ("hardener") in an appropriate solvent (1). (1) During combustion, polyurethanes are decomposed to a variety of combustion products, including isocyanates [2][3][4][5][6][7] whose health effects are discussed elsewhere [8][9][10]. However, it is important to mention that the causal relationship between isocyanates and the overall irritant effects is difficult to establish due to the presence of other irritant agents, e.g.…”

Evaluation of denuder sampling for a mixture of three common gaseous diisocyanates

“…This reaction is not thermally stable, which means that isocyanates will be regenerated and emitted into the surrounding air when PUR products are heated, e.g. during welding of metal sheets covered with paint containing PURs or hot-wire cutting of foam [1,2,3,4,5].…”