Simultaneous determination of third-generation synthetic cannabinoids in oral fluids using cyclodextrin-silica porous sorbents

A microporous material made of cyclodextrin units covalently immobilized into a silica network has found an innovative bioanalytical application in the sample clean-up and simultaneous isolation of three synthetic cannabinoids (ADB-CHMICA, MMB-CHMICA, and MDMB-CHMCZCA) from human oral fluid through solid-phase extraction. The subsequent quantitation is carried out using liquid chromatography coupled to fluorescence detection. The optimized experimental procedure gives recoveries ranging from 76% to 96% in oral fluid samples spiked with the studied cannabinoids at the µg L-1 level. High selectivity is obtained through the extraction procedure due to the presence of cyclodextrin in the silica network of the solid phase and thanks to the use of fluorescence detection in the separation technique. It is precisely the type of detection chosen that also gives the developed method a great sensitivity. The limits of detection of the proposed analytical method range from 0.11 to 0.73 µg kg−1 and high repeatability is observed, with variations lower than 6%. The obtained results demonstrate the versatility and high potential of cyclodextrin-silica porous materials for the sorption of the studied substances, contributing in a novel way to the proper determination of third-generation synthetic cannabinoids in biological samples.