Thermospray and Atomospheric Pressure Chemical Ionization Liquid Chromatographic-Mass Spectrometric Analysis of Benzodiazepines and Their Metabolites.

To assess the LC/MS methods for the determination of these compounds in biological materials positive ion mass spectra were measured for benzodiazepines and their metabolites by thermospray-liquid chromatography/mass spectrometry (TSP-LC/MS) and atomospheric pressure chemical ionization-liquid chromatography/mass spectrometry (APCI-LC/MS). In both TSP-LC/MS and APCI-LC/MS, LC analyses were performed on a TSKgel octyl-80Ts in the solvent system of methanol-ammonium acetate at a flow rate of 1.0 ml/min. TSP mass spectra showed only a [M+H]+ ion for most of compounds, while APCI mass spectra showed [M+H]+ and some fragment ions. The analysis of these compounds with TSP gave better detection limits than with APCI by scan mode, and gave the same results for detection limits as with APCI by selected ion monitoring (SIM). The data, described in this paper, should serve as a basis for the qualitative and quantitative analyses of benzodiazepines and their metabolites in biological samples.