Abstract

FERNANDEZ, Nicolas et al. Validation of a method for quantify 11-nor-9-carboxy-Δ⁹-tetrahydrocannabinol in human urine using solid phase extraction and gas chromatography-mass spectrometry. Acta toxicol. argent. [online]. 2016, vol.24, n.2, pp.116-127. ISSN 1851-3743.

Cannabis is one of the most widely used illegal drug in the world. Its consumption is related to different forensic, work, sports and clinical events. In order to determinate the presence of cannabis, different methods with distinct fundamentals and scopes (immunoassay and chromatography) are applied. This report described an accurate, reproducible, and validated gas chromatography-mass spectrometry (GC-MS) method for the quantitation of 11-nor-9-carboxy- Δ⁹-tetrahydrocannabinol (THCCOOH), the major metabolite of Δ⁹-tetrahydrocannabinol in urine. A solid phase extraction (SPE), previous alkaline hydrolysis, was performed on the urine sample. Its deuterated analog (THC-COOH D3) was used as internal standard. The GC-MS analysis made by selected ion monitoring (SIM). Calibration curve was linear over the specified range (10 -100 ng/ml; r > 0.999) and limit of quantitation was 10 ng/ml. Absolute recoveries ranged from 91.0 to 99.0. Intra-assay and inter assay precision ranged from 1.06 to 1.26 and 3.59 to 9.80 %, respectively. The method has been applied to real samples, positive to immunological screening test, resulting to be very useful and reliable in routine analysis of THC-COOH in human urine for toxicological purposes.

Keywords : 11-nor-9-carboxy- Δ⁹-tetrahydrocannabinol; Urine; Gas chromatography - mass spectrometry; Validation.