High-performance liquid chromatographic determination of Δ9-tetrahydrocannabinol and the corresponding acid in hemp containing foods with special regard to the fluorescence properties of Δ9-tetrahydrocannabinol

A solvent programmed reversed-phase HPLC method with UV detection for the determination of Δ9-tetrahydrocannabinol (THC) and Δ9-tetrahydrocannabinolic acid A (THCA-A) in foods containing parts of hemp such as edible oil, herb-teas (infusion), herbal hemp or hempseed is presented. The THC peak is also detected by fluorescence. The detection limits with UV detection are 0.01 ng for THC and 0.05 ng for THCA-A and with fluorescence detection 0.1 ng for THC. The relative standard deviation under repeatability conditions of the chromatographic procedure is about 0.5% and that of the over-all analytical procedure for THC in vegetable oils 2% (concentration range of 10–100 mg/kg).