title: Measurement of delta 1-tetrahydrocannabinol in plasma to the low picogram range by gas chromatography-mass spectrometry using metastable ion detection.
abstract: A method for the assay of delta 1-tetrahydrocannabinol (delta 1-THC) in plasma using combined gas chromatography-mass spectrometry with metastable ion monitoring is described. delta 1-THC was extracted with hexane and the extracts were methylated with diazomethane to shift the peaks produced by endogenous plasma constituents away from the cannabinoid region. The delta 1-THC was then converted into its trimethylsilyl derivative and quantitated using the metastable ion at m/z 371 formed in the M+ leads to [M - CH3]+ transition with [1",1",2",2"-2H4]cannabinol as the internal standard. delta 1-THC could be measured to 5 pg/ml in plasma. This assay is 20-100 times more sensitive than existing assays and has the advantage of not needing the usual extensive purification step.
mesh_terms: D000818:Animals; D013759:Dronabinol / Q000097:blood*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D002189:Marijuana Abuse / Q000097:blood; D011817:Rabbits
chemical_list: D013759:Dronabinol