Trace determination of tetrahydrocannabinol (THC) in cosmetic products by stir bar sorptive dispersive microextraction followed by liquid chromatography-tandem mass spectrometry

An analytical method for the determination of tetrahydrocannabinol (THC) at trace level in cosmetics is presented. As psychoactive compound, the presence of THC in consumer products should be avoided. However, it might be unintentionally present in cannabidiol-rich or hemp-based products by contamination or isomerization of cannabidiol. Due to the low concentrations expected, a sensitive and selective method is necessary for the analytical control of these products. In this sense, the presented method is based on stir bar sorptive dispersive microextraction (SBSDME) followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). In this work, a magnetic composite made of CoFe O magnetic nanoparticles embedded in a commercial reverse-phase polymer (Strata™-X-RP) was employed as magnetic sorbent material taking advantage of its affinity to the target analyte. Under the optimized conditions, the method was validated and showed good analytical features in terms of linearity (at least up to 10 ng mL ), limits of detection and quantification (2.2 and 7.2 ng g , respectively) and repeatability (RSD