Determination of clonazepam and its amino and acetamido metaoblites in human plasma by combined gas chromatography chemical ionization mass spectrometry and selected ion monitoring.

Our previously published gas chromatography chemical ionization mass spectrometry stable isotope dilution assay for clonazepam and its 7-amino metabolite in plasma has been modified to obtain more consistent recoveries of the amine metabolite and to permit the determination of the 7-acetamido metabolite of clonazepam. In addition, the manuscript describes the details of a method for a least squares analysis of the nonlinear standard curves associated with the use of certain stable isotope labeled analogs as internal standard.