Magnetic nanoparticles anchored with zeolites: An alternative material for dispersive magnetic solid-phase extraction for cannabinoids from urine samples

This study presents the development and validation of an analytical method using a magnetic sorption phase anchored with zeolites for cannabinoid extraction from urine samples of patients suspected of Cannabis sativa intoxication. High-performance liquid chromatography coupled with a diode array detector (HPLC-DAD) was employed for the identification and quantification of tetrahydrocannabinol (THC) and cannabidiol (CBD). Magnetic nanoparticles (MNPs) were synthesized using the coprecipitation method and anchored to zeolite, which was identified as the optimal natural sorbent phase. MNPs anchored with zeolites (MNPs@ZEO) were characterized using X-ray diffractometry, scanning and transmission electron microscopy, Fourier transform infrared spectroscopy (FT-IR), zeta potential, and particle size analysis. Multifactorial planning was conducted to optimize the dispersive magnetic solid-phase extraction (DMSPE) technique with MNPs@ZEO, with the best experimental condition being 15 mg of MNPs@ZEO, 1 min of agitation, 400 μL of sample and pH 7.0. The methodology was validated following bioanalytical guidelines, demonstrating linearity between 400 and 4000 μg/L for CBD and THC. Accuracy was obtained in relative error (RE%) and ranged from -8.66 to 5.69% and -6.91 to 8.14% for CBD and THC, respectively. Precision was obtained in coefficient variation (CV%) and ranged from 0.32 to 12.15% for CBD and from 0.45 to 14.93% for THC. Matrix effect was noticed only for THC. The method proved to be selective with no carryover. This DMSPE-HPLC-DAD approach was successfully applied to real urine samples.