Article
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A Quantitative 1H-NMR Method for Screening Cannabinoids in CBD Oils
Version 1
: Received: 14 May 2021 / Approved: 17 May 2021 / Online: 17 May 2021 (16:56:15 CEST)
A peer-reviewed article of this Preprint also exists.
Barthlott, I.; Scharinger, A.; Golombek, P.; Kuballa, T.; Lachenmeier, D.W. A Quantitative 1H NMR Method for Screening Cannabinoids in CBD Oils. Toxics 2021, 9, 136. Barthlott, I.; Scharinger, A.; Golombek, P.; Kuballa, T.; Lachenmeier, D.W. A Quantitative 1H NMR Method for Screening Cannabinoids in CBD Oils. Toxics 2021, 9, 136.
Abstract
Toxicologically relevant levels of the psychoactive ∆9-tetrahydocannabinol (∆9-THC) as well as high levels of non-psychoactive cannabinoids potentially occur in CBD (cannabidiol) oils. For consumer protection in the fast-growing CBD oil market, facile and rapid quantitative methods to determine the cannabinoid content are crucial. However, the current standard method, i.e., liquid chromatography combined with tandem mass spectrometry (HPLC-MS/MS), requires a time-consuming multistep sample preparation. In this study, a quantitative nuclear magnetic resonance spectroscopy (qNMR) method for screening cannabinoids in CBD oils was developed. Contrary to the HPLC-MS/MS method, this qNMR features a facile sample preparation, i.e., only diluting the CBD oil in deuterochloroform. Pulse length-based concentration determination (PULCON) enables a direct quantification using an external standard. The signal intensities of the cannabinoids were enhanced during the NMR spectra acquisition by means of multiple suppression of the triglycerides which are a major component of the CBD oil matrix. The validation confirmed linearity for CBD, cannabinol (CBN), ∆9-THC and ∆8-THC in hemp seed oil with sufficient recoveries and precision for screening. Comparing the qNMR results to HPLC-MS/MS data for 46 commercial CBD oils verified the qNMR accuracy for ∆9-THC and CBD but with higher limits of detection. The developed qNMR method paves the way for increasing the sample throughput as a complementary screening before HPLC-MS/MS.
Keywords
cannabidiol (CBD); ∆9-tetrahydrocannabinol (∆9-THC); cannabinol (CBN); ∆8-tetrahydrocannabinol (∆8-THC); cannabinoids; CBD oil; nuclear magnetic resonance spectroscopy (NMR); PULCON methodology; 1H NMR; qNMR
Subject
Chemistry and Materials Science, Food Chemistry
Copyright: This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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