The analysis of delta9-tetrahydrocannabinol and metabolite in whole blood and 11-nor-delta9-tetrahydrocannabinol-9-carboxylic acid in urine using disposable pipette extraction with confirmation and quantification by gas chromatography-mass spectrometry.

Essential to forensic laboratories is the desire to find a more sensitive, rapid method of analyzing Delta9-tetrahydrocannabinol (THC) and metabolite in biological specimens. Disposable pipette extraction (DPX) is a valuable method in extracting THC and 11-nor-Delta9-tetrahydrocannabinol-9-carboxylic acid (THCc) in blood and THCc in urine. Less waste and solvent usage; smaller specimen volume; clean chromatograms; and utilization of lowcost equipment and consumables were achieved using this method. Differing from traditional solid-phase extraction devices, DPX uses loosely packed sorbent allowing thorough mixing with the specimen without requiring vacuum for elution. Prior to extraction, urine specimens were hydrolyzed and proteins precipitated from blood. Specimen volume requirements were 1 mL of blood and 0.2 mL of urine. The limits of quantitation for THC and THCc in blood were 1 and 2 ng/mL, respectively, and 3 ng/mL for THCc in urine. With R2 values > or = 0.99, blood calibration curves were linear from 1 to 200 ng/mL and 2 to 500 ng/mL for THC and THCc, respectively, with urine THCc linear from 3 to 2000 ng/mL.