ONLINE IMMUNOAFFINITY EXTRACTION-COUPLED COLUMN CAPILLARY LIQUID-CHROMATOGRAPHY TANDEM MASS-SPECTROMETRY - TRACE ANALYSIS OF LSD ANALOGS AND METABOLITES IN HUMAN URINE

An on-line immunoaffinity extraction-coupled column capillary liquid c hromatography/tandem mass spectrometry (IAE/LC/LC/MS/MS) method is des cribed, The system involves three columns, a 2.1-mm-i.d. protein G imm unoaffinity column with noncovalently immobilized antibody specific to the analytes of interest, a packed capillary trapping column, and a p acked capillary analytical column, With use of a short packed capillar y trapping column, the protein G column could be operated at now rates of 2.5-4 mL/min while the packed capillary analytical column was main tained at a now rate of 3.5 mu L/min. Human urine diluted 1:1 with pho sphate-buffered saline was pumped directly onto the immunoaffinity col umn without pretreatment and was analyzed by electrospray mass spectro metry following the column switching process. Sample handling and tran sfer procedures were eliminated, The system was optimized and evaluate d for the determination of LSD, its analogs, and metabolites in spiked human urine at low part-per-trillion (ppt) levels using mass spectrom etric detection. LSD-positive human urine specimens from LSD users wer e also analyzed. Concentrations as low as 2.5 ppt of LSD and several o f its analogs were detected in spiked human urine using IAE/LC/LC/MS/M S. This is 20-fold below our previous limit of detection using solid p hase extraction and LC/MS/MS.