Conversion of 7-Carboxy-Cannabidiol (7-COOH-CBD) to 11-nor-9-Carboxy-Tetrahydrocannabinol (THC-COOH) During Sample Preparation for GC-MS Analysis

Factors influencing the in situ formation of Δ9-THC from cannabidiol during GC-MS analysis

Gas chromatography-mass spectrometry (GC-MS) is widely used for the identification of cannabinoids in seized plant material. Conditions used for instrumental analysis should maximize decarboxylation, while minimizing the in situ production of Δ9-THC inside the GC inlet. In this study, decarboxylation of the acidic Δ9-THC precursor and in situ degradation of cannabidiol (CBD) were investigated using seven commercial GC liners with different deactivation chemistries and geometries. While the inlet temperature was previously optimized at 250°C in a previously validated assay, we systematically examined the temperature-dependent decarboxylation of tetrahydrocannabinolic acid-A (Δ9-THCA-A) and cyclization of CBD between 230°C and 310°C using different liners using favorable and unfavorable conditions. Significant differences in decarboxylation rate and CBD cyclization were observed between different liner types. While no temperature-dependent differences in decarboxylation rate were observed within liner type, liner-dependent differences were observed (α = 0.05), particularly between those with different geometry. In contrast, temperature and liner-dependent differences were observed for in situ formation of Δ9-THC (α = 0.05). This was influenced by liner geometry and to a smaller extent by surface deactivation. Effects were exacerbated with liner usage. While significant differences were observed using new and used GC liners, differences between liners of the same type but different lot numbers were not observed. Inter-instrument differences using the same liner were also evaluated and had minimal effect. Liner- and temperature-dependent effects were also confirmed using more than 20 cannabis plant extracts. Careful selection of liner, inlet conditions, and regular preventive maintenance can mitigate the risks associated with in situ formation Δ9-THC from CBD.

Stability of Nano-Emulsified Cannabidiol in Acidic Foods and Beverages

Introduction: Food and beverage products containing cannabidiol (CBD) is a growing industry, but some CBD products contain Δ9-tetrahydrocannabinol (Δ9-THC), despite being labeled as "THC-free". As CBD can convert to Δ9-THC under acidic conditions, a potential cause is the formation of Δ9-THC during storage of acidic CBD products. In this study, we investigated if acidic products (pH ≤ 4) fortified with CBD would facilitate conversion to THC over a 2-15-month time period. Materials and Methods: Six products, three beverages (lemonade, cola, and sports drink) and three condiments (ketchup, mustard, and hot sauce), were purchased from a local grocery store and fortified with a nano-emulsified CBD isolate (verified as THC-free by testing). The concentrations of CBD and Δ9-THC were measured by Gas Chromatography Flame Ionization Detector (GC-FID) and Liquid Chromatography with tandem mass spectrometry (LC-MS/MS), respectively, for up to 15 months at room temperature. Results: Coefficients of variation (CVs) of initial CBD concentrations by GC-FID were <10% for all products except ketchup (18%), showing homogeneity in the fortification. Formation of THC was variable, with the largest amount observed after 15 months in fortified lemonade #2 (3.09 mg Δ9-THC/serving) and sports drink #2 (1.18 mg Δ9-THC/serving). Both beverages contain citric acid, while cola containing phosphoric acid produced 0.10 mg Δ9-THC/serving after 4 months. The importance of the acid type was verified using acid solutions in water. No more than 0.01 mg Δ9-THC/serving was observed with the condiments after 4 months. Discussion: Conversion of CBD to THC can occur in some acidic food products when those products are stored at room temperature. Therefore, despite purchasing beverages manufactured with a THC-free nano-emulsified form of CBD, consumers might be at some risk of unknowingly ingesting small amounts of THC. The results indicate that up to 3 mg Δ9-THC from conversion can be present in a serving of CBD-lemonade. Based on the previous studies, 3 mg Δ9-THC might produce a positive urine sample (≥15 ng/mL THC carboxylic acid) in some individuals. Conclusion: Consumers must exert caution when consuming products with an acidic pH (≤4) that suggests that they are "THC-Free," because consumption might lead to positive drug tests or, in the case of multiple doses, intoxication.

Automated extraction and LC-MS-MS analysis of 11-nor-9-carboxy-tetrahydrocannabinol isomers and prevalence in authentic urine specimens

11-Nor-9-carboxy-Δ9-tetrahydrocannabinol (Δ9-THCCOOH) is the most frequently detected illicit drug metabolite in the military drug testing program. An increasing number of specimens containing unresolved Δ8-THCCOOH prompted the addition of this analyte to the Department of Defense drug testing panel. A method was developed and validated for the quantitative confirmation of the carboxylated metabolites of Δ8- and Δ9-THC in urine samples utilizing automated pipette tip dispersive solid-phase extraction and analysis by liquid chromatography-tandem mass spectrometry (LC-MS-MS). Analytes were separated isocratically over an 8.5-min runtime and detected on an MS-MS equipped with an electrospray ionization source operated in negative mode. A single point calibrator (15 ng/mL) forced through zero demonstrated linearity from 3 to 1,000 ng/mL. Intra- and inter-day precision were ≤9.1%, and bias was within ±14.1% for Δ8-THCCOOH and Δ9-THCCOOH. No interferences were found after challenging the method with different over-the-counter drugs, prescription pharmaceuticals, drugs of abuse and several cannabinoids and cannabinoid metabolites, including Δ10-THCCOOH. Urine specimens presumptively positive by immunoassay (n = 2,939; 50 ng/mL Δ9-THCCOOH cutoff) were confirmed with this analytical method. Δ8-THCCOOH and Δ9-THCCOOH were present together above the 15 ng/mL cutoff in 33% of specimens. However, nearly one-third of the specimens analyzed were positive for Δ8-THCCOOH only. This manuscript describes the first validated automated extraction and confirmation method for Δ8- and Δ9-THCCOOH in urine that provides adequate analyte separation in urine specimens with extreme isomer abundance ratios.

Fast and sensitive LC-MS/MS method for quantification of cannabinoids and their metabolites in plasma of cattle fed hemp

Hemp-based materials have gained interest as alternative feed ingredients for livestock. However, safety concerns arise regarding the transfer of cannabinoids from the plant to the animals. Addressing these concerns requires the use of methods capable of detecting and quantifying cannabinoids in livestock. In this study, a fast and sensitive method was developed for quantification of cannabinoids and cannabinoid metabolites in cattle plasma using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The extraction of cannabinoids from the plasma matrix was achieved by combining the Captiva Enhanced Matrix Removal-Lipid clean-up and salting-out assisted liquid-liquid extraction procedure. The developed method underwent validation using various analytical parameters, and the results demonstrated good accuracy, precision, specificity, and high sensitivity. The method was applied to real plasma samples obtained from cattle fed hemp for 2 weeks, and successfully detected various cannabinoids, including delta-9-tetrahydrocannabinol. Furthermore, the study revealed that 7-carboxy cannabidiol, a metabolite of cannabidiol, was the predominant cannabinoid present in the cattle plasma throughout the feeding period, which could remain detectable for weeks after the hemp feeding had ended.

Application of gas chromatography in the analysis of phytocannabinoids: An update (2020-2023)

INTRODUCTION

Cannabinoids are a group of compounds that bind to cannabinoid receptors. They possess pharmacological properties like that of the plant Cannabis sativa. Gas chromatography (GC) is one of the popular chromatographic techniques that has been routinely used in the analysis of cannabinoids in different matrices.

OBJECTIVE

The article aims to review the literature on the application of GC-based analytical methods for the analysis of phytocannabinoids published during the period from January 2020 to August 2023.

METHODOLOGY

A thorough literature search was conducted using different databases, like Web of Knowledge, PubMed, Google Scholar, and other relevant published materials including published books. The keywords used, in various combinations, with cannabinoids being present in all combinations, in the search were cannabinoids, Cannabis sativa, marijuana, analysis, GC, quantitative, qualitative, and quality control. From the search results, only the publications that incorporate the GC analysis of phytocannabinoids were reviewed, and papers on synthetic cannabinoids were excluded.

RESULTS

Since the publication of the review article on GC analysis of phytocannabinoids in early 2020, several GC-based methods for the analysis of phytocannabinoids have appeared in the literature. While simple 1D GC-mass spectrometry (MS) and GC-flame ionisation detector (FID) methods are still quite common in phytocannabinoids analysis, 2D GC-MS and GC-MS/MS are increasingly becoming popular, as these techniques offer more useful data for identification and quantification of phytocannabinoids in various matrices. The use of automation in sample preparation and the utilisation of mathematical and computational models for optimisation of different protocols have become a norm in phytocannabinoids analysis. Pre-analyses have been found to incorporate different derivatisation techniques and environmentally friendly extraction protocols.

CONCLUSIONS

GC-based analysis of phytocannabinoids, especially using GC-MS, remains one of the most preferred methods for the analysis of these compounds. New derivatisation methods, ionisation techniques, mathematical models, and computational approaches for method optimisation have been introduced.

Determination of urinary metabolites of cannabidiol, Δ8-tetrahydrocannabinol, and Δ9-tetrahydrocannabinol by automated online μSPE-LC-MS/MS method

In this study, an automated online micro-solid-phase extraction (μSPE)-liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the detection of metabolites of cannabidiol (CBD), Δ⁸-tetrahydrocannabinol (Δ⁸-THC), and Δ⁹-tetrahydrocannabinol (Δ⁹-THC), particularly 7-carboxy- cannabidiol (7-COOH-CBD), 11-nor-9-carboxy-Δ⁸-tetrahydrocannabinol (Δ⁸-THCCOOH), 11-nor-9-carboxy-Δ⁹-tetrahydrocannabinol (Δ⁹-THCCOOH), and 11-nor-9-carboxy-Δ⁹- tetrahydrocannabinol-glucuronide (Δ⁹-THCCOOH-glu) in urine. An instrument top sample preparation (ITSP) cartridge was introduced to increase the sensitivity toward analytes and decrease the matrix effect of the urine. LC-MS/MS analysis was performed in the multiple-reaction monitoring mode, and the analytes were separated using an Acquity UPLC HSS T3 (2.1 × 100 mm, 1.8 µm) column and gradient elution with water containing 0.05 % acetic acid and methanol as the mobile phase. The calibration range was 0.5-200 ng/mL for all the analytes, with a correlation coefficient (r) of ≥0.996 and a weighting factor of 1/x². The limits of detection for 7-COOH-CBD, Δ⁸-THCCOOH, Δ⁹-THCCOOH, and Δ⁹-THCCOOH-glu were 0.06, 0.02, 0.03, and 0.1 ng/mL, respectively. The intra- and inter-day accuracy ranged from -8.0 to 6.2 % and -7.3 to 7.8 % with a precision of ≤7.2 % and ≤6.2 %, respectively. The method was also validated for selectivity, recovery, matrix effect, stability, and dilution integrity. The developed method was successfully applied to the analysis of 78 urine samples, and 7-COOH-CBD, Δ⁸-THCCOOH, Δ⁹-THCCOOH, and Δ⁹-THCCOOH-glu were detected in 54 urine samples at normalized concentrations of 1.1, 0.6-939.1, 0.9-2595.0, and 1.3-527.6 ng/mg creatinine, respectively.

Will tetrahydrocannabinol be formed from cannabidiol in gastric fluid? An in vivo experiment

Cannabidiol (CBD) products have ascribed an uprising trend for their health-promoting effects worldwide. In contrast to Δ⁹-tetrahydrocannabinol (THC), CBD exhibits no state of euphoria. Since conversion of CBD into THC in an acidic environment has been reported, it has not been proved whether this degradation will also occur in human gastric fluid. A total of 9 subjects ingested 400 mg CBD as a water-soluble liquid together with lecithin as an emulsifier and ethanol as a solubilizer. Blood samples were taken up to 4 h, and urine samples were submitted up to 48 h. THC, 11-hydroxy-Δ⁹-THC (THC-OH), 11-nor-9-carboxy-Δ⁹-THC (THC-COOH), CBD, 7-hydroxy cannabidiol (7-OH-CBD), and 7-carboxy cannabidiol (7-CBD-COOH) were determined in blood and THC-COOH and 7-CBD-COOH in urine by LC-MS/MS. Neither THC, THC-OH, nor THC-COOH were detectable in any serum specimen. Only two urine samples revealed THC-COOH values slightly above the threshold of 10 ng/ml, which could also be caused by trace amounts of THC being present in the CBD liquid. It can be concluded that negative consequences for participants of a drug testing program due to a conversion of CBD into THC in human gastric fluid appear unlikely, especially considering a single intake of dosages of less than 400 mg. Nevertheless, there is a reasonable risk for consumers of CBD products being tested positive for THC or THC metabolites. However, this is probably not caused by CBD cyclization into THC in human gastric fluid but is most likely due to THC being present as an impurity of CBD products.