Comparison of HPLC and GC-MS for measurement cocaine and metabolites in human urine.

High-performance liquid chromatography (HPLC) was compared with gas chromatography-mass spectrometry (GC-MS) for quantitation of cocaine, benzoylecgonine, norcocaine, and cocaethylene in urine. Calibration standards were prepared in human urine, and bupivacaine was added as the internal standard for quantitation. After solid-phase extraction, the reconstituted samples were divided into aliquots for analysis by HPLC and GC-MS. The analytical performance of the two methods were compared with regard to sensitivity, precision, and dynamic range. Results of GC-MS and HPLC analyses of nine urine specimens previously confirmed as positive for benzoylecgonine were compared. Analytical results by HPLC were comparable to GC-MS. Therefore, for many laboratories, HPLC is a useful alternative to GC-MS for measuring cocaine and metabolites in urine.