Is acetone really in your extracts or did it come from beyond?
Last week, we introduced the solvent acetone which has been found in cannabis and hemp extracts confusing the recipients of the data. How did a solvent that wasn’t used in the extraction process result in this contamination? We established that under specific chemical conditions, terpenes can react with atmospheric ozone, hydroxyl radicals, or nitric oxide to form acetone.
But acetone has also been quantified in hemp and cannabis products where none would have been expected, such as hemp-derived terpenes. This was reported to us by Joshua Jones, Ph.D., organic chemist and founder of the consulting firm Jonesing Labs LLC, who has received 3rd-party analytical lab results confirming not just acetone, but toluene as well after running a residual solvent profile on hemp-derived terpenes.
Acetone might also be a byproduct of the plants’ natural metabolic processes, as the plants contain terpenes and over 500 other chemical ingredients.  I spoke with Chris Hudalla, Ph.D., Chief Scientific Officer of ProVerde Labs, who reported quantifiable levels of multiple solvents, such as methanol, ethanol, isopropanol, and acetone after being asked by a client to run a residual solvents panel on their biomass.
Did these solvents form as natural metabolites from the biomass, or did volatile constituents sampled from the biomass, like terpenes, further degrade within the gas chromatogram (GC) itself, resulting in a false positive? Or did the solvent hit come from its use in the lab? Some instruments are so sensitive that they might measure miniscule solvent levels in the environment; so, establishing that the lab isn’t a source of contamination is intrinsically important to identifying the root cause.
While ProVerde is further investigating terpene degradation at different GC settings, Hudalla reports seeing similar false positive results with cinnamon-flavored vape oils. Cinnamaldehyde, a molecule important in defining the organoleptic profile of cinnamon, formed benzene and benzaldehyde within the GC. Hudalla said they could create more benzene by changing the inlet parameters on their GC, illustrating an unexpected role that analytical instrumentation can play.
So, while solvent-based extraction of Cannabis sativa indeed warrants residual solvent testing, the source of solvents well-outside those traditionally used, like acetone, are worthy of further investigation before freaking out thinking that your concentrate is contaminated.
References Gonçalves, J. et al. “Cannabis and Its Secondary Metabolites: Their Use as Therapeutic Drugs, Toxicological Aspects, and Analytical Determination.” Medicines, vol.6, no.31, 2019, doi:10.3390/medicines6010031. [journal impact factor = 2.133; times cited 11 (ResearchGate)]
Image Credit: Growing Marijuana Pro