Application of surface ionization methods for highly sensitive and selective analysis of benzodiazepine derivatives

In this work, the results of studying the possibilities of surface ionization mass spectrometry (SI/MS) and atmosphere pressure thermodesorption surface ionization (APTDSI) spectroscopy for high-sensitivity and selective detection and identification of psychotropic preparations of benzodiazepine derivatives--medazepam, diazepam and chlordiazepoxide--are presented. It has been established that the SI mass spectra of benzodiazepines have a small number of lines and are significantly different from those obtained by electron ionization (EI) and that the molecules of benzodiazepines can be ionized by surface ionization with high efficiency (> or = 100 times and more than by EI) and the current density increases from diazepam to medazepam. It has been found that the APTDSI spectra of benzodiazepine derivatives have two characteristic maxima connected with energy of sublimation and desorption. The ionization efficiency is several C/g (Coulomb per gram), the linear range of the concentration dependence is 3-4 orders of a magnitude. The results obtained by the SI/MS and APTDSI methods have been compared with those obtained by the conventional TLC and GC/MS with electron ionization.