LC-MS-(TOF) analysis method for benzodiazepines in urine samples from alleged drug-facilitated sexual assault victims

In recent years there has been an increase in the number of reports in the U.S. of the use of drugs to commit sexual assault. In 1994, a nationwide urine testing program was developed to assess the incidence of the use of drugs to facilitate sexual assault and provide information for use in the investigation of these crimes. Urine samples were collected from victims of suspected drug-induced sexual assault by law enforcement agencies, emergency rooms, and rape crisis centers. The most implicated drug class was benzodiazepines, either alone or in combination with alcohol. In this report, a procedure was developed for the screening of 22 benzodiazepines in human urine by liquid chromatography-time of flight-mass spectrometry [LC-MS-(TOF)]. The limit of quantitation for all benzodiazepines ranged from 2 to 10 ng/mL, and the limit of detection was 0.5 to 3.0 ng/mL. These results suggest that the method sensitivity is suitable to screen for all 22 benzodiazepines in human urine at low levels. The method was used to analyze samples previously reported to have screened positive for benzodiazepines by immunoassay at 50 ng/mL cut off but failed to confirm by a gas chromatography-MS method. The results of reanalysis of these samples using this LC-MS method are reported.