ISSN:
0306-042X
Keywords:
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Δ9-Tetrahydrocannabinol and two of its metabolites, 11-hydroxy-Δ9-tetrahydrocannabinol and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol, can be measured in a single 1-ml sample of blood, plasma, or urine by a new assay which combines a relatively rapid extraction procedure with capillary column gas chromatography and negative ion chemical ionization mass spectrometry. Deuterium-labeled analogs of each cannabinoid are added to the physiological specimen as internal standards. Two extracts are obtained from each sample: a neutral fraction containing Δ9-tetrahydrocannabinol and 11-hydroxy-Δ9-tetrahydrocannabinol, and an acid fraction containing 11-nor-9-carboxy-Δ9-tetrahydrocannabinol. The neutral fraction is derivatized by treatment with trifluoroacetic anhydride; the acid fraction is first treated with BF3-methanol followed by reaction with trifluoroacetic anhydride. Under electron-capture chemical ionization conditions the derivatized Δ9-tetrahydrocannabinol and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol give abundant molecular anions ideally suited for selected ion monitoring. The negative ion chemical ionization spectrum of the HO-THC-trifluoroacetate shows no molecular anion. Consequently, quantitation of the hydroxy metabolite is achieved by monitoring a fragment ion formed by loss of CF3CO2 from its molecular anion. The limits of reliable measurement are judged to be 0.1 ng ml-1 for 11-nor-9-carboxy-Δ9-tetrahydrocannabinol, 0.2 ng ml-1 for Δ9-tetrahydrocannabinol and 0.5 ng ml-1 for 11-hydroxy-Δ9-tetrahydrocannabinol. Four examples are given of the application of the assay to the analysis of specimens of medico-legal importance.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bms.1200100503
