Identification of Diuron and Four of Its Metabolites in Human Postmortem Plasma and Urine by LC/MS with a Moving-Belt Interface

Unknown compounds that were not amenable to GC/MS were found during routine benzodiazepine HPLC screening in a postmortem case. The apparent thermolability made the application of liquid chromatography with mass spectrometry mandatory. The moving-belt interface was used because of its value for identification based on the use of both electron impact and chemical ionization, which provided information on both structure and molecular weight. The herbicide diuron and four of its metabolites were identified in plasma and urine and had a total concentration as high as 100 mg/L. Metabolism via demethylation and hydroxylation appeared to be the major routes.