Analysis of the major metabolite of delta 9-tetrahydrocannabinol in urine. III. A GC/ECD procedure.
A gas chromatographic/electron capture detection procedure was developed for the analysis of 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid in urine. Hydrolyzed urine samples (1 mL or less) were extracted by a simple acid-base partitioning step. The extracted metabolite was derivatized with pentafluorobenzyl bromide in a biphasic system using benzyl tributylammonium hydroxide as a phase transfer catalyst. 11-Nor-cannabinol-9-carboxylic acid was used as internal standard. A linear relationship was observed between the peak height ratio of the metabolite/internal standard and the concentration of the metabolite (r = 0.9996), and between the peak height and concentration of the metabolite (r = 0.9995). Concentration of 5 ng/mL of metabolite in urine resulted in a peak-to-noise ratio of 4:1; however, concentrations down to 1 to 2 ng/mL could be determined. The procedure has many advantages over currently available methods, of which sensitivity and speed are the most important.
D002849:Chromatography, Gas / Q000379:methods*; D013759:Dronabinol / Q000031:analogs & derivatives* / Q000378:metabolism* / Q000652:urine; D006801:Humans
C016780:11-nor-delta(9)-tetrahydrocannabinol-9-carboxylic acid; D013759:Dronabinol