Monitoring of Dinitrotoluene and its metabolites in urine by spectrophotometry of their coupled aryldiazonium salts.

A rapid, accurate method was developed for monitoring employee absorption of dinitrotoluene (DNT). The method reduces DNT and its metabolites in urine to primary arylamines, diazotizes them with nitrous acid, then couples the diazo compounds with N-(1-Naphthyl)ethylenediamine, producing a colored complex. Spectrophotometric analysis of the colored complexes at 550 nm provides a measure of DNT absorption. The chemistry prevents interferences from all but primary arylamines and compounds reduced to primary arylamines. A six-month monitoring program of employees at a DNT manufacturing facility was conducted. Control samples from individuals not exposed to DNT were used to define an exposure indication level. The exposure indication level was used to correlate DNT exposure with job description or individual activity and was defined as apparent DNT and metabolite concentrations greater than 38 micrograms/ml. Group exposure also was indicated and associated with plant activity. Job description were ranked according to a rational evaluation of exposure potential and correlated well with monitoring data.