DETERMINATION OF COCAINE IN BODY FLUIDS BY GAS CHROMATOGRAPHY WITH SURFACE IONIZATION DETECTION: COMPARISON WITH NITROGEN-PHOSPHORUS DETECTION
Abstract
Cocaine has been found to be measurerable by gas chromatography (GC) with surface ionization detection (SID), with high sensitivity. The calibration curve showed satisfactory linearity in the range of 0.1-5.0 ng on column; the detection limit of cocaine-HCI was about 20 pg on column (0.5-1.0 ng/ml of a sample). Cocaine could be extracted from human whole blood and urine with Bond Elut Certify columns, with satisfactory recovery and low backgrounds. After establishment of a detailed procedure of extraction of the drug from human samples, capillary gas chromatograms were obtained with both SID and nitrogen-phosphorus detection (NPD). Much more impurity peaks appeared with NPD than with SID for both whole blood and urine; the cocaine peak partially overlapped an impurity peak with NPD, but not with SID.