Mass fragmentographic determination of urinary amine metabolites in rats exposed to degradation products from heated rigid polyurethane.

A mass fragmentographic method was developed for the urinalysis of amine metabolites in rats resulting from inhalation of thermally induced degradation products of rigid polyurethane synthesized from the aromatic diisocyanate 4,4'-bis(carbonylamino)diphenylmethane. The urinary excretion of acetylated 4,4'-bis(amino)-diphenylmethane was determined after acid hydrolysis, followed by alkaline extraction in toluene and derivatization with heptafluorobutyric acid anhydride. The excretion was linearly correlated to the inhaled parent isocyanate at three different degradation temperatures. Mass spectrometric detection of the amines also allowed comparison with the degraded polymer, which should be of considerable forensic significance. The sensitivity (5 pg/microliter) also enables biological monitoring of occupational exposure in the production and engineering of polyurethane articles.