Metal organic frameworks as advanced materials for the paper-based extraction of synthetic cannabinoids in oral fluids

In this manuscript, a paper-based device modified with metal-organic frameworks was applied for the extraction of synthetic cannabinoid receptor agonists (SCRAs) in oral fluids, taking profit of the several interaction mechanisms between MOF-analytes, followed by their quantification by LC-fluorescence detection. The resulting composite, named as NH₂-UiO-66@paper, was characterized by different techniques such as infrared, scanning electron microscopy, among others. The extraction procedure was optimized by using a full factorial design after an appropriate selection of the significant variables. Once the method was optimized, the analytical parameters were studied including liner range (LOQ-400 µg L⁻¹), limit of detection (0.7 to 2.8 µg L⁻¹) and intra- and inter-batch precision (<8 and <20%, expressed as RSD, respectively). Next, the accuracy of the method was assessed at three different concentration levels (25, 75 and 100 µg L⁻¹), obtaining values comprised from 64 to 98%. Finally, the method was applied for the analysis of oral fluids (n=25) (15 positives and 10 negative samples) and sensitivity, specificity and accuracy (efficiency) of the methodology were calculated obtaining 80, 100 and 88%, respectively.