Thermal decomposition of CBD to Δ9-THC during GC-MS analysis: A potential cause of Δ9-THC misidentification

Development and validation of a sensitive and simultaneous liquid chromatography tandem mass spectrometry method for the determination of eight phytocannabinoids in various CBD products

In this study, we developed and validated a liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the simultaneous determination of eight phytocannabinoids in various cannabidiol (CBD) products from Japanese market. This method was combined with electrospray ionization in positive mode and sample preparation with QuEChERS. Three types of commercial products such as honey, chocolate, and gummies were used to perform accurate quantification with unified protocol of LC-MS/MS and QuEChERS. The limit of detection and quantification were 5-20 µg g-1 and 10-40 µg g-1, respectively. Reproducibility was ensured using matrices free of target foods, resulting in an accuracy within ±10 % and a precision with a relative standard deviation of less than 5 % for all targets. Finally, this analytical method was applied to 8 series of commercial samples from the Japanese market. This unified protocol will serve as a reference as an official method in Japan.

A systematic review of analytical methodologies capable of analysing phytocannabinoids in cosmetics

As cannabidiol (CBD) is not considered to be a drug and because of its potential health claims, it is an interesting compound that is often found in cosmetics. However, the safety of CBD, as well as the presence of trace amounts of other phytocannabinoids, including the psychoactive substance ∆9-tetrahydrocannabinol (THC), is still being debated. A robust analytical technique capable of analysing cosmetic products and determining their phytocannabinoid content will be crucial in assessing the safety of these products. This systematic review aims to highlight the current analytical tools that could be used to analyse phytocannabinoids in cosmetics. The ideal method would be able to analyse high levels of CBD in combination with trace levels of THC and their acids. The method should provide good recoveries and accuracies in a variety of matrices while providing information on up-coming phytocannabinoids such as cannabichromene (CBC), cannabigerol (CBG) and cannabinol (CBN). The systematic review approach was based on the Preferred Reporting Items for Systematic review and Meta-Analyses method. The research focused on studies published from January 2010 to December 2022 in PubMed and Scopus. A total of 15 datasets met the inclusion and exclusion criteria and were tabulated to allow easy comparison. Although some of the reviewed methods can handle multiple matrices and provide satisfactory recoveries, this review process did not identify an ideal method. The most suitable methods either could not quantify phytocannabinoid acids or were not sensitive enough to quantify trace levels of psychoactive phytocannabinoids.

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.

Analyte protectant approach to protect amide-based synthetic cannabinoids from degradation and esterification during GC-MS analysis

The forensic analysis of amide-based synthetic cannabinoids (SCs) in seized materials is routinely performed using gas chromatography-mass spectrometry (GC-MS); however, a major challenge associated with GC-MS is the thermolytic degradation of substances with sensitive functional groups. Herein, we report the comprehensive thermal degradation and ester transformation of amide-based SCs, such as AB-FUBINACA, AB-CHMINACA, and MAB-CHMINACA, during GC-MS analysis and their treatment with analyte protectants (APs). These SCs were found to undergo thermolytic degradation during GC-MS in the presence of non-alcohol solvents. Using methanol as an injection solvent resulted in the conversion of the amide group to an ester group, producing other SCs such as AMB-FUBINACA, MA-CHMINACA, and MDMB-CHMINACA. Degradant and ester product formation has been interpreted as the adsorption of target SCs on glass wool via hydrogen bonding interactions between the active silanol and amide groups of the SCs, followed by an addition and/or elimination process. The factors found to influence the thermal degradation and/or esterification of the amide functional group include residence time, activity of glass wool, and injection volume. This report presents the fragmentation patterns of all compounds that were produced by degradation and esterification. Using 0.5 % sorbitol (AP) in MeOH as an injection solvent resulted in complete protection and improvement of the chromatographic shape of the compounds. This method has been successfully confirmed in terms of sensitivity, linearity, accuracy, and precision for standard solutions and tablet extraction using 0.5 % sorbitol in MeOH. Using AP increased the sensitivity by ten times or more compared to the use of only MeOH. The limit of detection for all analytes was determined as 25 ng/mL, and the calibration curves were linear over the concentration range of 50-2000 ng/mL. The values of accuracy error were below 11 %, and precision was less than 13 %. The effects of phytochemicals of herbal products, tablet ingredients, and biological matrices on the degradation and/or esterification and APs performance have also been evaluated in this work.

Comprehensive cannabinoid profiling of acid-treated CBD samples and Δ8-THC-infused edibles

Δ8-Tetrahydrocannabinol (Δ8-THC) is increasingly popular as a controversial substitute for Δ9-tetrahydrocannabinol (Δ9-THC) in cannabinoid-infused edibles. Δ8-THC is prepared from cannabidiol (CBD) by treatment with acids. Side products including Δ9-THC and other isomers that might end up in Δ8-THC edibles are less studied. In this paper, three orthogonal methods, namely reversed-phase (RP)-UHPLC-DAD/HRMS, normal-phase/argentation (silica-Ag(I))-HPLC-DAD/MS, and GC-FID/MS were developed for analysis of cannabinoid isomers, namely Δ8-THC, Δ9-THC, CBD, Δ8-iso-THC, Δ(4)8-iso-THC, and hydrated THC isomers. Eight acid-treated CBD mixtures contained various amounts of Δ8-THC (0-89%, w/w%), high levels of Δ9-THC (up to 49%), Δ8-isoTHC (up to 55%), Δ(4)8-iso-THC (up to 17%), and three hydrated THC isomers. Commercial Δ8-THC gummies were also analyzed, and issues like overclaimed Δ8-THC, excessive Δ9-THC, undeclared Δ8-iso-THC, and Δ(4)8-iso-THC were found. These findings highlight the urgency of improving regulations towards converting CBD to Δ8-THC for use as food ingredients.

Quality test of cannabidiol profiling in CBD oil products and evaluation of residual THC at high temperature based on liquid chromatography coupled with tandem mass spectrometry

Cannabidiol (CBD) oil products are available in Japan as cosmetics, fragrances, food and items. Herein, quality testing of cannabinoid profiling in CBD oil products and the evaluation of possible residual tetrahydrocannabinol (THC) in these products using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was conducted. A simple, sensitive, and selective LC-MS/MS assay (electrospray positive ion mode) was employed for the simultaneous quantification of eight cannabinoids. This quantification with three different oil samples showed that accuracy rates ranged from 87.7 to 106.9% (RSD > 3.5%). Furthermore, the quantification limit of THC is 0.001 mg/g of CBD oil products for suitable levels lower than the regulatory value. Notably, this method was used to evaluate CBD oil products from the Japanese market. Additionally, we investigated the THC conversion in CBD oil products at a high temperature (70°C) which has a minor effect on CBD stability in oil products with additives. Herein, the developed LC-MS/MS assay is applied to monitor the quality of CBD, trace THC and other components in CBD oil products.

The analysis of cannabinoids in e-cigarette liquids using LC-HRAM-MS and LC-UV

The use of cannabidiol or CBD products has skyrocketed in the last five years due to the alleged therapeutic benefits, a low potential for abuse and lack of the typical psychoactive effects associated with the use of cannabis products containing high levels of ∆9-tetrahydrocannabinol (∆9-THC). In Belgium, CBD-containing e-liquids with a total THC content lower than 0.2% (w/w) are currently legal. In order to verify the compliance of the different CBD-containing e-cigarette liquids that are available to the Belgian population, a method was developed for screening of 17 cannabinoids and to quantify the major cannabinoids such as CBD, CBDA, ∆9-THC and ∆9-THCA. The latter was fully validated using the 'total error' approach, applying accuracy profiles and conforming to ISO17025. None of the analysed samples exceeded the legal limit for the total amount of ∆9-THC present. However, of the 20 CBD-liquids investigated in this study, only 30% of the samples contained an amount of CBD that was within 10% deviation of the label claim. Moreover, the CBD e-liquids labelled "full/broad spectrum" consisted of several minor alkaloids in comparison to the "classic" CBD e-liquids where the acidic forms of the cannabinoids were not present. Currently, no legislation is available for the regulation of CBD e-liquids, however these results indicate that quality controls are pertinent especially concerning the discrepancy in CBD label accuracy.

Comments on “discrepancies between validated GC‐FID and UHPLC‐DAD methods for the analysis of Δ‐9‐THC and CBD in dried hemp flowers”

The original article described difference of total Δ⁹ -THC contents determined by gas chromatography with flame ionization detection (GC-FID) and high-performance liquid chromatography with ultraviolet detection (HPLC-UV). We presumed that this difference was mainly caused by peak overlapping of Δ⁹ -THC and presumptive cannabielsoin (CBE) isomer on the GC chromatogram.