Performance evaluation of three liquid chromatography mass spectrometry methods for broad spectrum drug screening

Background: Liquid chromatography-mass spectrometry (LC-MS) and tandem LC-MS (LC-MS/MS) are increasingly used in toxicology laboratories as a complementary method to gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-ultraviolet detection (LC-UV) for comprehensive drug screening (CDS). This study was designed to characterize the sensitivity and specificity of three LC-MS(/MS) vendor-supplied methods for targeted CDS and identify the current limitations associated with the use of these technologies. Methods: Five methods for broad spectrum CDS, including LC-UV (REMEDi), full scan GC-MS, LC-MS (ZQu (TM)-Mass Detector with MassLynx (TM)-software), LC-QTRAP-MS/MS (3200-QTRAP (R) with Cliquid (R)-software) and LC-LIT-MS/MS (LXQ (TM) Linear Ion Trap with ToxID (TM)-software) were evaluated based on their ability to detect drugs in 48 patient urine samples. Results: The tandem MS methods identified 15% more drugs than the single stage MS or LC-UV methods. Use of two broad spectrum screening methods identified more drugs than any single system alone. False negatives and false positives generated by the LC-MS(/MS) software programs were identified upon manual review of the raw data. Conclusions: The LC-MS/MS methods detected a broader menu of drugs: however, it is essential to establish manual data review criteria for all LC-MS(/MS) drug screening methods. Use of an EI-GCC-MS and ESI-LC-MS/MS combination for targeted CDS may be optimal due to the complementary nature of the chromatographic and ionization techniques. (C) 2010 Elsevier B.V. All rights reserved.