Precision Testing Reveals CBD Oil Accuracy

This study presents the development of a HiSorb microextraction method coupled with thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) for analyzing cannabidiol (CBD) in commercial hemp oils. Two HiSorb sorptive coatings were evaluated, triple-phase polydimethylsiloxane (PDMS)/carbon wide-range (CWR)/divinylbenzene (DVB) and double-phase PDMS/CWR, for their extraction efficiencies. The triple-phase HiSorb, combined with water-bath incubation for 2 h at 80 °C, delivered the highest CBD recovery. The developed HiSorb-TD-GC-MS method showed excellent linearity (R2 = 0.9951), with a method limit of detection (LOD) of 30 µg/mL and a limit of quantification (LOQ) of 100 µg/mL. The total chromatographic runtime was 11.2 min. Precision was satisfactory, with intra-day RSD % ranging from 6.8 to 7.3% and inter-day RSD % ranging from 6.5 to 7.7%. Recoveries at three concentration levels for diluted sample (low 100 μg/mL, medium 300 μg/mL, high 500 μg/mL) ranged from 77.2 to 86.4%. No detectable formation of Δ9-THC was observed, confirming that the method does not induce isomerization of CBD during GC analysis. Greenness assessment yielded AGREE = 0.75 (analytical method) and AGREEprep = 0.54 (sample preparation). The developed method was applied to commercial hemp oil samples and revealed no significant statistical difference (p > 0.05) between the label claim and measured CBD concentration in all tested samples. The application of green analytical methods contributes to sustainability by minimizing environmental impact and enhancing resource efficiency.