Development and validation of a liquid chromatography-tandem mass spectrometry (LC-MSMS) procedure for screening of urine specimens for 100 analytes relevant in drug-facilitated crime (DFC).
In recent years, drug-facilitated crime (DFC) has become an increasing problem. A minimum list of 80 analytes to be monitored in such cases has been proposed by the Society of Forensic Toxicologists (SOFT) including the recommended minimum performance limits (RMPL). In the present study, two liquid chromatography-tandem mass spectrometry-based screening procedures, one in positive (method I) and one in negative (method II) electrospray ionization mode were developed and validated. Gradient elution was performed on a ZORBAX Eclipse XDB-C18 column after protein precipitation of the urine samples. Detection was carried out in the scheduled multiple reaction monitoring (MRM) mode monitoring two transitions per compound. A total of 100 analytes (91 basic in method I and nine acidic in method II) could be identified using the described procedure. No interferences were observed in 30 tested blank urine samples. The RMPLs were achieved for all analytes and ranged from 1 ngmL for fentanyl to 10 μgmL for γ-hydroxybutyrate (GHB). Matrix effects (ME) were evaluated using the same 30 urine samples and ranged from -90 % for tetrazepam to >6,000 % for the 11-nor-9-carboxy-tetrahydrocannabinol (THC-COOH). The relative standard deviations of ME were below 25 % for the vast majority of analytes. Results for urine specimens from nine authentic DFC cases were always negative with exception of drugs prescribed to the victims. Reanalysis with the developed procedure of 24 urine samples, with a positive screening result during routine clinical toxicology analysis, confirmed the routine findings. In an excretion study after a single oral doxylamine dose (30 mg), the parent drug and its nor metabolite could be detected in urine specimens from a young female volunteer for 10 days. The developed procedure allows a selective and sensitive screening of urine samples for almost all recommended analytes relevant in DFC cases.