Rapid isolation with Sep-Pak C18 cartridges and wide-bore capillary gas chromatography of benzophenones, the acid-hydrolysis products of benzodiazepines.

A simple extraction procedure with a Sep-Pak C18 cartridge for benzophenones and their detection after separation by wide-bore capillary gas chromatography (GC) are presented. The benzodiazepine-containing samples, after heating in acid and centrifugation, were passed through the cartridges and eluted with chloroform. Except for bromazepam, the recoveries of benzodiazepines detected as benzophenones were excellent. Separation of each benzophenone peak from impurities was achieved with an intermediately polar HP-17 capillary column. Electron capture detection gave sensitivity more than 10 times higher than that of flame ionization detection.