4,4'-METHYLENEDIANILINE IN HYDROLYZED SERUM AND URINE FROM A WORKER EXPOSED TO THERMAL-DEGRADATION PRODUCTS OF METHYLENE DIPHENYL DIISOCYANATE ELASTOMERS

A 45-year-old mechanic employed in blowing hot air (350 degrees-600 de grees C) onto the surface of a polyurethane methylene diphenyl diisocy anate (MDI) conveyer belt developed dyspnoea, rhinoconjunctivitis and fever. The illness was suggestive of an MDI-associated illness, compat ible with both immediate hypersensitivity and a complement-mediated im mune-complex reaction. In his serum there were specific IgG and IgE an tibodies against MDI and other isocyanates, and high values of circula ting immune complexes. The patient's blood and urine samples were anal ysed for the presence of 4,4'-methylenedianiline (MDA) in hydrolysed u rine and plasma. MDA was derivatized to amides using pentafluoropropio nic acid anhydride (PFPA). Gas chromatography-mass spectrometry determ inations were made monitoring the (M-20; M = molecular mass) fragments from the MDA-PFPA and the [H-2(2)] MDA-PFPA derivative. The first uri ne sample was obtained 22 h and the last sample 114 h after start of e xposure. The urine concentrations of MDA were corrected for creatinine . The half-time of MDA was 70-80 h. The first serum sample was obtaine d 19 h and the last sample 1967 days after the start of exposure. The half-time was 21 days, which suggests the presence of MDI/MDA plasma p rotein adducts in the exposed worker.