DIAZEPAM AND DESMETHYLDIAZEPAM QUANTITATION IN WHOLE-BLOOD BY NITROGEN-SENSITIVE DETECTOR AFTER DERIVATIZATION

A reliable procedure is presented for the quantitation of diazepam and its physiologically active metabolite by use of the nitrogenphosphorous detector (NPD). The problem of quantitation of desmethyldiazepam due to tailing on certain liquid phases such as OV-1 is circumvented by derivatization of the drug to its corresponding “N-propyl” derivative which has a response to NPD detection 1.2 times that of diazapam. Within-run coefficients of variation for drug concentrations of 0.25, 0.50, and 1.5 μg/mL were between 3 and 8%.Day-to-day variation for the derivatizatio, of desmethyldiazepam at levels of 125 ng/mL and a 750 ng/mL in whole blood was 5% and 7%, respectively. © 1979 Oxford University Press.