Clean Screen® THC Sorbent Cited in THC-COOH Validation Paper

Of all the analytical methods available to forensic toxicologists, testing for cannabinoids is one most requested extraction approaches via the technical support team. Cannabis is one of the most widely used illegal drugs in the world. Its consumption is related to various forensic, work, sports and clinical concentrations. In order to determinate the presence of cannabis, different methods with distinct fundamentals and scopes (immunoassay and chromatography) are applied.  In a recent paper authored by Nicolas Fernandez et al., from Universidad de Buenos Aires published in Acta Toxicol. Argent. ((2016) 24 (2): 116-127) UCT’s world famous Clean Screen^® THC was employed as the extraction sorbent in 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.

The solid phase extraction (SPE) was performed after samples of urine had been previously subjected to alkaline hydrolysis. To ensure efficiency of the process the deuterated analog (THC-COOH D₃) was used as internal standard. The GC-MS analysis performed in selected ion monitoring (SIM) after chemical modification of the SPE extracts with MSTFA.  The constructed calibration curve was linear over the specified range (10 -100 ng/mL; r² > 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. After validation, the method has been applied to real samples, positive to immunoassay screening test, resulting to be very useful and reliable in routine analysis of THC-COOH in human urine for toxicological purposes. This paper demonstrates why forensic toxicologists across the world turn to UCT for the world’s finest SPE sorbents when extracting cannabinoid metabolites from biological matricies.