Gas chromatographic analysis of ketamine and norketamine in plasma and urine: nitrogen-sensitive detection.

A sensitive gas chromatographic method for quantitative analysis of ketamine and norketamine in human and animal biological fluids is described. The nitrogen-sensitive detection procedure used is more stable than electron-capture detection and reduced analysis time. The method used bromo-ketamine as an internal standard for quantitation and is linear from 10-25,000 ng/ml. No interferences were shown with drugs commonly associated with cardiac surgery with cardiopulmonary by-pass. This assay is sensitive, specific, using either native or derivatized drugs and can be used for routine analysis of ketamine and norketamine in plasma or urine.