engleski

SPE-GC-MS determination of THC, THC-OH and THC-COOH in urine samples

Cannabis is the most commonly used illicit drug in the world. Therefore, there is a great demand for reliable and sensitive methods for determining their presence in biological samples. Its use is detected by determining the presence of the main active compound Δ9-tetrahydrocannabinol (THC) and its metabolites 11-hydroxy-Δ9-tetrahydrocannabinol (THC-OH) and 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH). An analytical method based on solidphase extraction (SPE) and gas chromatography-mass spectrometry (GC-MS) has been developed and validated for confirming THC, THC-OH and THC-COOH in urine samples. Analytes were extracted from urine using molecularly imprinted polymer (MIP) with methacrylic acid (MAA) as functional monomer (130 mg) and THC-OH as target molecule. Before extraction, urine samples were base-hydrolysed, acidifi ed to pH 3, and diluted to total volume of 6 mL. Elution was performed with chloroform and ethyl acetate (60:40 v/v). Dry extracts were silylated with BSTFA+1% TMCS at room temperature for 30 minutes. One μL of silylated extract was injected to the GC-MS instrument. Detection and quantifi cation were made in the single-ion recording mode. The developed method was linear over the range from LOQ to 150 ng mL-1 for all three analytes. LOD for THC, THC-OH, and THC-COOH was 2.5 ng mL-1, 1.0 ng mL-1, and 1.0 ng mL-1, and LOQ was 3 ng mL-1, 2 ng mL-1 and 2 ng mL-1, respectively. The precision, accuracy, recovery, and matrix effect were investigated at 5 ng mL-1, 25 ng mL-1, and 50 ng mL-1. In the investigated concentration range, recoveries were 76.1 % to 79.4 % for THC, 77.7 % to 81.9 % for THC-OH and 68.1 % to 72.8 % for THC-COOH. Optimised and validated method was successfully applied to 15 post-mortem urine samples positive to cannabinoides.

development and validation of analytical method; extraction; metabolites; molecularly imprinted polymer; post-mortem urine samples; tetrahydrocannabinol

nije evidentirano