Advancing the Precision of Cannabis Testing

By its very nature, analytical testing is a numbers game. No matter what kind of sample is being tested, what it’s being tested for, or what the results show, every data point created informs us and moves us closer to a better understanding of cannabis. As the industry has continued to gain mainstream acceptance, we’ve been able to pursue new opportunities that serve to refine our testing methods and advance the data we obtain from every test we run.

In 2013, when MCR Labs was incorporated and about to begin testing some of the very first medicinal cannabis products in Massachusetts, company President Michael Kahn and Director of Scientific Operations Scott Churchill had developed and validated their first cannabinoid profile. This first iteration of this analysis was able to quantify 5 different cannabinoids–THCA, CBDA, THC, CBD, and CBN. These cannabinoids were prioritized because testing for some of them was required for product compliance and there were analytical standards of them available. Analytical standards are suitably pure compounds of known concentration that act as the “guide” that enables the machines to find and quantify them in a sample. 

The cannabinoid testing method eventually grew to include 12 unique cannabinoids, and after that, the method was expanded to 17 and then quickly to the 19 cannabinoid method that MCR Labs utilizes today (and more to come!). This expansion was possible thanks to the acquisition of more sensitive equipment as well as analytical standards for additional cannabinoids that were not previously available. With each expansion, the testing became more valuable to the patients, producers, and researchers we test for because the increase of total cannabinoids shows a more detailed composition of the full cannabinoid profile for a given flower or product. 

Additionally, the quantification of each cannabinoid became more precise with every new cannabinoid added to the scope of the test. This is because cannabinoids are structurally very similar on a molecular level, so trace amounts of certain minor cannabinoids outside of the testing scope can sometimes be detected “under the curve” of a target cannabinoid. This is called “coelution” and refers to the problem in chromatography where two or more chemical compounds can occur and be separated at nearly the same time. 

Luckily, this isn’t something that significantly impacted any of our data because we run exhaustive validation experiments to pinpoint when this happens. What it does tell us is that there is another compound to be separated here. So, when we found coelution occurring with THCA, we knew there were cannabinoids outside of our scope in the sample we were testing. It was just a matter of obtaining the pure analytical standards and figuring out what they were. 

Now that we have expanded our scope to include additional analytes, we are able to see CBL and CBC, which elute very close to THCA. This increases the selectivity of the testing and means we can quantify THCA and every other cannabinoid more precisely. 

New cannabinoids are still being discovered, and as analytical standards for more cannabinoids become commercially available, labs like ours will be able to further expand cannabinoid profiling. As this happens across the cannabis testing industry, it will help researchers by providing them with more concrete data to push their discoveries to the next level.