Abstract
Liquid chromatography-tandem mass spectrometry (LC-MS-MS) offers specific advantages over gas chromatography-mass spectrometry (GC-MS) such as the ability to identify and measure a broader range of compounds with minimal sample preparation. Comparative analysis of LC-MS-MS versus GC-MS was performed for urinalysis detection of five benzodiazepine compounds currently part of the Department of Defense (DoD) Drug Demand Reduction Program (DDRP) testing panel; alpha-hydroxyalprazolam, oxazepam, lorazepam, nordiazepam and temazepam. In the analyses of internally prepared control urine samples at concentrations around the DDRP administrative decision point for benzodiazepines (100 ng/mL), both technologies produced comparable results with average accuracies between 99.7 and 107.3% and average coefficients of variation (%CV) <9%. Analysis of service member specimens that screened positive for benzodiazepines using both technologies produced comparable results for all analytes. Different degrees of matrix effect were observed for all analytes in the LC-MS-MS analysis. However, the effects were controlled by using deuterated internal standards (ISTDs). Additionally, there was a 39% increase in nordiazepam mean concentration analyzed by LC-MS-MS due to suppression of the ISTD ion by the flurazepam metabolite 2-hydroxyethylflurazepam. The ease and speed of sample extraction, the broader range of compounds that can be analyzed and shorter run time make the LC-MS-MS technology a suitable and expedient alternative confirmation technology for benzodiazepine testing.