engleski

Modified QuEChERS extraction and GC-MS analysis of selected cannabinoids from human urine

The aim of this work is to apply a modified QuEChERS method to extract cannabinoids from urine, using a mixture of salts for extraction in an appropriate ratio instead of commercially available cartridges. The analysis was performed on blank urine to which a known concentration of tetrahydocannabinol (THC), cannabinol (CBN) and cannabidiol (CBD), 11- hydroxy-Δ9-tetrahydrocannabinol (THC-OH) and 11-nor-9-carboxy-Δ9- tetrahydrocannnabinol (THC-COOH) was added. Six solvents, as well as four solvent mixtures, were tested for extraction and the solvent mixture acetonitrile: dichloromethane (1:3) was selected for which the best recovery factor was obtained. Derivatization of all samples was done with MSTFA (N-trimethylsilyl-N-methyl trifluoroacetamide) + 1% TMCS (2, 2, 2- Trifluoro-N-methyl-N-(trimethylsilyl)- acetamide, chlorotrimethylsilane) at room temperature. The prepared extracts were analyzed by a coupled system, gas chromatography- mass spectrometry (GC-MS) in full-scan mode. Peaks of selected cannabinoids are well separated indicating that there was no interference with the selected analytes. The results were calculated from a calibration curve ranging from LOQ to 1000 ng/mL for selected cannabinoids with a correlation factor over 0.998. The LOD and LOQ for THC are (3.0 ng/mL ; 9.0 ng/mL), for CBN (5.0 ng/mL ; 18.0 ng/mL) for CBD (5.0 ng/mL, 16.0 ng/mL), for THC-OH (2.6 ng/mL ; 8.7 ng/mL) and for THC-COOH (5.0 ng/mL ; 15.0 ng/mL). The recovery factor was recorded in the range of 79.40% for THC- COOH to 94.86% for CBN. The modified QuEChERS extraction method can be used for routine analysis of selected cannabinoids. This method was successfully applied on real samples and thirty urine samples were analyzed.

Quechers Extraction ; Cannabinoids ; THC ; GC-MS ; Urine

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