Pipette tip micro-solid phase extraction (octyl-functionalized hybrid silica monolith) and ultra-high-performance liquid chromatography-tandem mass spectrometry to determine cannabidiol and tetrahydrocannabinol in plasma samples.
This manuscript describes the development of an innovative method to determine cannabinoids (cannabidiol and tetrahydrocannabinol) in human plasma samples by pipette-tip micro-SPE and LC-MS/MS. An octyl-functionalized hybrid silica monolith, which had been synthesized and characterized, was used as a selective stationary phase. The octyl-functionalized hybrid silica monoliths presented high permeability and adequate mechanical strength. The micro-SPE variables (sample pH, draw-eject cycles, solvent for phase clean-up, and desorption conditions) were investigated to improve not only the selectivity but also the sorption capacity. The method was linear at concentrations ranging from the lower limit of quantification (10.00 ng.mL-1 ) to the upper limit of quantification (150.0 ng.mL-1 ). The lack of fit and homoscedasticity tests, as well as the determination coefficients (r2 greater than 0.995), certified that linearity was adequate. The precision assays presented CV (coefficient of variation) values lower than 15%, and the accuracy tests provided RE (relative error) values ranging from 3.2% to 14%. Neither significant carry-over nor matrix effects were detected. Therefore, the pipette tip micro-SPE /LC-MS/MS method has demonstrated to be adequate to determine cannabidiol and tetrahydrocannabinol simultaneously in plasma samples for therapeutic drug monitoring of patients undergoing treatment with cannabinoids. This article is protected by copyright. All rights reserved.
Keywords: cannabidiol; octyl-functionalized hybrid silica monolith; pipette tip micro-solid phase extraction; tetrahydrocannabinol, plasma samples.