At Restek, we’re into medical marijuana, from an analytical standpoint, as cannabis is one of the most complex (and controversial) natural products. That complexity can make it very challenging to analyze, especially as the suite of analytes expands beyond the usual cannabinoids (e.g. delta-9-THC, cannabidiol, cannabinol) to include other cannabinoids (e.g. cannabigerol, cannabichromene, delta-8-THC, cannabivarin, etc.) and terpenes, sesquiterpenes, oxygenated terpenes, and pesticides.
Except for the pesticides, many of the compounds listed above either have medicinal properties, or contribute to what is called the “entourage effect”. Simply put, this is where an “extract” of a natural product, which contains many compounds, including what is normally thought of as the active ingredient, is more effective in treatment than the pure active ingredient alone. Medical marijuana researchers are especially interested in plants that have higher cannabidiol concentrations, as cannabidiol possibly has antioxidant, anticonvulsant, anti-anxiety, and anti-nausea properties, as well as having cytotoxic behavior towards cancer cells. We recently analyzed 100 seized marijuana samples and found that while most had negligible cannabidiol (CBD) content, four contained CBD that ranged from 0.8 to 4.8%. More later in another blog on that subject.
We had originally hoped that we could do one extraction procedure (QuEChERS) and determine cannabinoids, pesticides, terpenes, sesquiterpenes, and oxygenated terpenes (using different dilutions and GC and LC runs, of course), but that may be unrealistic, especially for terpenes, which are relatively volatile. Given that the QuEChERS procedure generates heat when MgSO4 and water are mixed, some of the terpenes are likely lost during extraction, which would lead to a low-biased quantification. Static or dynamic headspace analysis, or SPME, may be more appropriate for terpene analysis.
Stay tuned for more information on our new analytical efforts in this field and be sure and review the old stuff by going to ChromaBLOGraphy and then using the Search field type in “marijuana” or “cannabis”.