Determination of benzodiazepine in tablets studied by thermal desorption gas chromatography

Thermal desorption gas chromatography (TDGC) was applied to the analysis of 13 kinds of tablets containing different benzodiazepines (BZDs). An aliquot of ground tablet sample (0.1-1 mg), weighed into a platinum sample cup, was placed in a furnace pyrolyzer where the sample was heated up to a suitable temperature (150-500 degrees C) so that BZD was desorbed from the sample powder. The desorbed components of BZDs were immediately transferred into a separation column by a helium carrier gas without using any trapping techniques. The desorbed components were identified by TDGC-mass spectrometry. Among various BZDs, fludiazepam, nimetazepam and mexazolam in tablet samples were determined by the present method. Thus, the results obtained were in good agreement with the specified values. Correlation coefficients of the calibration lines for the three BZDs' ranged from 0.997 to 0.999 for several micrograms to about 10 microg of the components. Relative standard deviations of this method were < 4.1% for 4 or 5 runs.