DEVELOPMENT OF A GAS-CHROMATOGRAPHY - MASS-SPECTROMETRY METHOD FOR DETERMINATION OF KETAMINE IN PLASMA AND ITS APPLICATION TO HUMAN SAMPLES

A sensitive and precise gas chromatography-mass spectrometry method wi th selected ion monitoring has been developed for identification and q uantification of the phencyclidine derivative ketamine in human plasma . The assay is based on an alkaline extraction from aqueous to organic solvent from plasma and on an efficient gas chromatographic separatio n on a DB-5 capillary column. The analytical procedure has a coefficie nt of variation of 0.7-6.2% and from 1.3 to 8.7% within-day and from d ay-to-day analysis, respectively. The low level of sensitivity was 10 ng/ml. It was used to measure low plasma concentrations in volunteers during ketamine-induced experimental psychosis. The method is not enan tio selective.