Simultaneous measurement of urinary ketamine, norketamine, and dehydronorketamine by liquid chromatography-atmospheric pressure chemical ionization mass spectrometry

A liquid chromatography/atmospheric pressure ionization mass spectrometry has been developed for the determination of ketamine, norketamine, and dehydronorketamine in human urine. A separation of these analytes in urine samples without tedious pretreatment procedures has been achieved within 10 min. Linear calibration curves of these analytes with coefficients better than 0.998 have been obtained over a wide range from 12.5 to 200 ng/mL. The accuracy was between 2.1% and 7.2% with detection limits at levels of 0.02 ng/mL, 0.02 ng/mL and 0.93 ng/mL for ketamine, norketamine and dehydronorketamine, respectively. The results demonstrate the suitability of the liquid chromatography/atmospheric pressure ionization mass spectrometry approach to analyze trace ketamine, norketamine and dehydronorketamine in urine. Urinary ketamine and norketamine levels were relatively low at 4-24 h intervals and were difficult to assay in a normal laboratory. In the present study, the determination of urinary dehydronorketamine levels at 2-24 hours appears to have a great potential for use in Schedule III controlled drugs management.