Molecularly imprinted polymer solid-phase extraction of 10 cannabis-related compounds from human urine and plasma samples

To enforce the law on cannabis use, it is necessary to establish a simple and efficient method for the extraction of cannabinoids and their metabolites from human biological specimens. Molecularly imprinted polymers (MIPs) are highly cross-linked polymers that can recognize and capture target compounds sterically and electrostatically. Solid-phase extraction (SPE) methods using MIP as adsorbents have been widely developed for selective extraction of target analytes. In this study, we evaluated the extraction efficacy of the following 10 cannabis-related compounds in human urine and plasma samples using a commercially available MIP-SPE cartridge: Δ9-tetrahydrocannabinol (THC), Δ8-THC, tetrahydrocannabivarin, cannabigerol, cannabichromene, cannabidiol, cannabinol, 11-nor-9-carboxy-Δ9-THC, 11-nor-9-carboxy-Δ8-THC, and 11-hybroxy-Δ9-THC. The MIP-SPE method combined with liquid chromatography–tandem mass spectrometry exhibited good linearity of calibration curves (correlation coefficients, > 0.994 for urine and > 0.999 for plasma) in the concentration ranges of 10–1000 ng/mL, detection sensitivities from sub-ng/mL to ng/mL levels, and satisfactory precisions (< 14 % for urine and < 4.8 % for plasma) and accuracies (within ± 21 % for urine and ± 11 % for plasma). The recovery rates were 49–102 % for urine and 34–87 % for plasma, and matrix effects were 49–91 % for urine and 45–108 % for plasma. The proposed method is expected to be applicable for the extraction and quantification of cannabinoids and their metabolites in actual human biological samples.