Acetone as Artifact of Analysis in Terpene Samples by HS-GC/MS.

Cannabis-infused product manufacturers often add terpenes to enhance flavor. Meanwhile, labeling requirements for these same products necessitate testing for residual solvent levels. We have found that heating terpene samples containing an oxygen or air atmosphere results in the detection of significantly higher levels of acetone when compared to the same compound in argon atmosphere using temperature regimes common to headspace autosampler routines. This formation was statistically significant (p = 0.05) for most of the predominant terpenes found in cannabis. The largest increase in acetone formation was seen for terpinolene which showed an 885% increase in oxygen atmosphere (4603.6 PPM) when compared to analysis under argon (519.9 PPM). Cannabinoids were shown to reduce this formation and explain why high levels of acetone are not reported in cannabis extracts, even though these can contain up to 40% terpenes.

Cannabis Inflorescence for Medical Purposes: USP Considerations for Quality Attributes.

There is an active and growing interest in cannabis female inflorescence (Cannabis sativa) for medical purposes. Therefore, a definition of its quality attributes can help mitigate public health risks associated with contaminated, substandard, or adulterated products and support sound and reproducible basic and clinical research. As cannabis is a heterogeneous matrix that can contain a complex secondary metabolome with an uneven distribution of constituents, ensuring its quality requires appropriate sampling procedures and a suite of tests, analytical procedures, and acceptance criteria to define the identity, content of constituents (e.g., cannabinoids), and limits on contaminants. As an independent science-based public health organization, United States Pharmacopeia (USP) has formed a Cannabis Expert Panel, which has evaluated specifications necessary to define key cannabis quality attributes. The consensus within the expert panel was that these specifications should differentiate between cannabis chemotypes. Based on the secondary metabolite profiles, the expert panel has suggested adoption of three broad categories of cannabis. These three main chemotypes have been identified as useful for labeling based on the following cannabinoid constituents: (1) tetrahydrocannabinol (THC)-dominant chemotype; (2) intermediate chemotype with both THC and cannabidiol (CBD); and (3) CBD-dominant chemotype. Cannabis plants in each of these chemotypes may be further subcategorized based on the content of other cannabinoids and/or mono- and sesquiterpene profiles. Morphological and chromatographic tests are presented for the identification and quantitative determination of critical constituents. Limits for contaminants including pesticide residues, microbial levels, mycotoxins, and elemental contaminants are presented based on toxicological considerations and aligned with the existing USP procedures for general tests and assays. The principles outlined in this review should be able to be used as the basis of public quality specifications for cannabis inflorescence, which are needed for public health protection and to facilitate scientific research on cannabis safety and therapeutic potential.

Understanding dabs: contamination concerns of cannabis concentrates and cannabinoid transfer during the act of dabbing.

Cannabis concentrates are gaining rapid popularity in the California medical cannabis market. These extracts are increasingly being consumed via a new inhalation method called 'dabbing'. The act of consuming one dose is colloquially referred to as "doing a dab". This paper investigates cannabinoid transfer efficiency, chemical composition and contamination of concentrated cannabis extracts used for dabbing. The studied concentrates represent material available in the California medical cannabis market. Fifty seven (57) concentrate samples were screened for cannabinoid content and the presence of residual solvents or pesticides. Considerable residual solvent and pesticide contamination were found in these concentrates. Over 80% of the concentrate samples were contaminated in some form. THC max concentrations ranged from 23.7% to 75.9% with the exception of one outlier containing 2.7% THC and 47.7% CBD. Up to 40% of the theoretically available THC could be captured in the vapor stream of a dab during inhalation experiments. Dabbing offers immediate physiological relief to patients in need but may also be more prone to abuse by recreational users seeking a more rapid and intense physiological effect.

Determination of pesticide residues in cannabis smoke.

The present study was conducted in order to quantify to what extent cannabis consumers may be exposed to pesticide and other chemical residues through inhaled mainstream cannabis smoke. Three different smoking devices were evaluated in order to provide a generalized data set representative of pesticide exposures possible for medical cannabis users. Three different pesticides, bifenthrin, diazinon, and permethrin, along with the plant growth regulator paclobutrazol, which are readily available to cultivators in commercial products, were investigated in the experiment. Smoke generated from the smoking devices was condensed in tandem chilled gas traps and analyzed with gas chromatography-mass spectrometry (GC-MS). Recoveries of residues were as high as 69.5% depending on the device used and the component investigated, suggesting that the potential of pesticide and chemical residue exposures to cannabis users is substantial and may pose a significant toxicological threat in the absence of adequate regulatory frameworks.

Artemisinin and sesquiterpene precursors in dead and green leaves of Artemisia annua L. crops.

This paper analyses the accumulation and concentrations of the antimalarial artemisinin in green and dead leaves of Artemisia annua crops in two field experiments. Concentration differences were analysed as being determined by (a) the total production of artemisinin plus its upstream precursors dihydroartemisinic acid, dihydroartemisinic aldehyde, artemisinic aldehyde and artemisinic alcohol and (b) the conversion of precursors towards artemisinin. Concentrations of the total of artemisinin plus its precursors were higher in green leaves than in dead leaves in the younger crop stages, but were comparable at the final harvests. In every crop stage, the conversion of precursors to artemisinin was more advanced in dead leaves than in green leaves. This resulted in the molar concentrations of artemisinin being higher in dead leaves than in green leaves at the final harvests. The molar quantity of dihydroartemisinic acid, the last enzymatically produced precursor, was higher than that of artemisinin in green leaves, but only 19 - 27% of that of artemisinin in dead leaves. Dead leaves were very important for the final artemisinin yield. They constituted on average 34% of the total leaf dry matter and 47% of the total artemisinin yield at the final harvests. The possibility to convert a larger part of dihydroartemisinic acid into artemisinin during post-harvest handling is discussed.