Chromatographic determination of amines in biological fluids with special reference to the biological monitoring of isocyanates and amines : II. Determination of 2,4- and 2,6-toluenediamine using glass capillary gas chromatography and selected ion monitoring

Abstract

A capillary gas chromatographic method, using selected ion monitoring in the electron impact mode, was developed for the analysis of 2,4- and 2,6-toluenediamine (TDA), ( C.A. Nos. 95-80-7 and 823-40-5) in aqueous solutions and human urine. The method is based on basic extraction of TDA from 2 ml of hydrolysed urine into toluene. The TDA was derivatized to an amide using a perfluorofatty anhydride. Three anhydrides were investigated, trifluoroacetic anhydride, TFAA ( C.A. No. 407-25-0), pentafluoropropionic anhydride, PFPA ( C.A. No. 356-42-3) and heptafluorobutyric anhydride, HFBA ( C.A. No. 336-59-4). Trideuterated 2,4- and 2,6-TDA, (C 2H 3C 6H 3(NH 2) 2), were synthesized and used as internal standards. The molecular ions of TDA-amides ( m/z = 314, 414 and 514) and the trideuterated TDA ( m/z = 317, 417 and 517) were monitored. The correlation coefficient was 0.999 for 2,4-TDA and 0.998 for 2,6-TDA (0.3–8 μg/l) for the monitoring of molecular ions, and the correlation coefficient was 0.999 for 2,4-TDA and 0.998 for 2,6-TDA (0.3–8 μg/l) for the monitoring of m/z = 295 and 298 fragments of TDA-PFPA and trideuterated TDA-PFPA. The detection limit of TDA in human urine was ca. 0.1 μg/l. Hydrolysed urine from an exposed worker was found to contain 4 μg of TDA/l, with a workroom atmsphere of 1–10 μg/m 3 TDI. The overall recovery for PFPA derivatives was found to be 96 ± 4 for 2,4- and 106 ± 5% for 2,6-TDA from water and 100 ± 4 and 109 ± 6% from urine.