DETERMINATION OF COMPLEX-MIXTURES OF AIRBORNE ISOCYANATES AND AMINES .2. TOLUENE DIISOCYANATE AND AMINOISOCYANATE AND TOLUENEDIAMINE AFTER THERMAL-DEGRADATION OF A TOLUENE DIISOCYANATE-POLYURETHANE

An LC-MS method is presented for the determination of thermal decompos ition products of polyurethane, The method is based on the collection of air samples in midget impinger flasks containing 0.01 mol l(-1) dib utylamine (DBA) dissolved in toluene, DBA reacts with isocyanates to g ive urea derivatives, The amines simultaneously collected were derivat ized with ethyl chloroformate (ET) to give urethane derivatives, Two i somers of toluene diisocyanate (2,4- and 2,6-TDI), toluene-2,4- and -2 ,6-diamine (TDA), three isomers of toluene aminoisocyanates and oligom ers with two and three aromatic rings were determined in air containin g thermal decomposition products of TDI-polyurethane. LC with gradient elution, at 0.5 ml min(-1) starting with acetonitrile-water (46 + 54) and ending after 14 min with acetonitrile-water (77.5 +/- 22.5) and a tmospheric pressure ionization monitoring of positive ions demonstrate d highly sensitive and selective determinations, Quantification was pe rformed by monitoring the molecular ion [M + 1](+) of TDI-DBA and TDA- ET derivatives, The instrumental detection limit was 1 nmol l(-1) of T DI-DBA and 2 nmol l(-1) of TDA-ET. Linear calibration curves were obta ined and the correlation coefficient was 0.9981-0.9996 for 50-500 nmol l(-1) (n = 14), The over-all precision for samples spiked at a concen tration of 500 nmol l(-1) of 2,4- and 2,6-TDA-ET and 2,4- and 2,6-TDI- DBA was 1.7, 1.6, 1.8 and 1.9% (n = 11), respectively.