Chocolate muddles cannabis potency testing

August 25, 2019

Science Daily/American Chemical Society

In 2012, Washington and Colorado became the first states to legalize recreational marijuana. Since then, several other states have joined them, and cannabis-infused edibles, including gummy bears, cookies and chocolates, have flooded the market. But these sweet treats have created major headaches for the scientists trying to analyze them for potency and contaminants. Researchers now report that components in chocolate might be interfering with cannabis potency testing, leading to inaccurate results.

The researchers will present their results at the American Chemical Society (ACS) Fall 2019 National Meeting & Exposition.

"My research focuses on cannabis potency testing because of the high stakes associated with it," says David Dawson, Ph.D., the project's principal investigator. "If an edible cannabis product tests 10% below the amount on the label, California law states that is must be relabeled, with considerable time and expense. But it's even worse if a product tests 10% or more above the labeled amount -- then the entire batch must be destroyed."

Manufacturers add cannabis to a wide variety of foods, and the composition of these products, also known as the "matrix," can affect potency testing results. Dawson and his colleagues at CW Analytical Laboratories decided to focus on potency testing for cannabis-infused chocolates because they are a very common product. CW Analytical Laboratories is a cannabis testing lab in Oakland, California, where recreational marijuana became legal in 2018. "We also noticed, kind of anecdotally, some weird potency variations depending on how we prepared chocolate samples for testing," he says. So Dawson studied the effects of altering sample prep conditions, such as the amounts of chocolate and solvent, pH and type of chocolate, on the concentration of Δ9-tetrahydrocannabinol (Δ9-THC; the major psychoactive constituent of cannabis) measured by high-performance liquid chromatography (HPLC).

Their results were surprising. "When we had less cannabis-infused chocolate in the sample vial, say 1 gram, we got higher THC potencies and more precise values than when we had 2 grams of the same infused chocolate in the vial," Dawson says. "This goes against what I would consider basic statistical representation of samples, where one would assume that the more sample you have, the more representative it is of the whole." These results suggested that some other component of the chocolate -- a matrix effect -- was suppressing the signal for Δ9-THC.

"Simply changing how much sample is in the vial could determine whether a sample passes or fails, which could have a huge impact on the producer of the chocolate bars, as well as the customer who might be under- or overdosing because of this weird quirk of matrix effects," he notes.

Now Dawson is trying to figure out which ingredient of chocolate is responsible for the matrix effects. He has tried spiking a standard solution of Δ9-THC with varying amounts of chocolate bar, cocoa powder, baker's chocolate and white chocolate, all of which have different components, and observing how the HPLC signal changes. "Our best lead right now is that it has something to do with the fats, which makes sense considering that Δ9-THC is fat-soluble," Dawson says.

The team would like to extend their analyses to other cannabinoids, such as cannabidiol (CBD), a non-psychoactive substance that is cropping up in many edible products. Also, they plan to investigate other food matrices, such as chocolate chip cookies. Dawson says that he hopes the research will contribute toward developing standard methods for cannabis potency testing in a variety of edibles. "We owe this research to the scientific community, the producers and the consumers," he says. "We have to be able to provide highly accurate and precise testing across a wide swath of matrices."

https://www.sciencedaily.com/releases/2019/08/190825075930.htm

Faster test for cannabis quality

New method to help meet increasing demand for cannabis potency testing

May 17, 2018

Science Daily/University of British Columbia Okanagan campus

Researchers have developed a new method of measuring phytocannabinoids -- the primary bioactive molecules in cannabis -- that will lead to faster, safer and more accurate information for producers, regulators and consumers alike.

With the coming legalization of cannabis in Canada, producers are increasingly looking for quick and accurate means of determining the potency and quality of their products.

Researchers at UBC's Okanagan campus have developed a new method of measuring phytocannabinoids -- the primary bioactive molecules in cannabis -- that will lead to faster, safer and more accurate information for producers, regulators and consumers alike.

"There is growing demand on testing labs from licensed cannabis growers across the US and Canada who are under pressure to perform potency testing on ever-increasing quantities of product," says Matthew Noestheden, PhD chemistry student under Prof. Wesley Zandberg at UBC's Okanagan campus. "Traditional tests can take upwards of 20 minutes to perform, where we can do it in under seven. It will save a great deal of time and money for producers with enormous greenhouses full of thousands of samples requiring testing."

Noestheden says that not only can he test the substance in record time, but he can also test for a virtually limitless number of phytocannabinoid variants.

"Most people are familiar with THC as the primary bioactive compound in cannabis. But in reality, there are more than 100 different phytocannabinoid variants, many with their own unique biological effects," says Noestheden. "The problem is that it's very difficult to differentiate between them when testing cannabis potency."

The research team overcame the problem by using high-pressure liquid chromatography -- an instrument that isolates each phytocannabinoid to measure them independently. They were able to discern the potency of 11 unique phytocannabinoids in cannabis extracts, which is important for determining the safety and authenticity of cannabis products.

"We tested twice as many phytocannabinoids compared to what most labs are testing for now, and more than twice as fast," says Noestheden. "We limited our tests to 11 variants because these were the only ones commercially available at the time. We could just as easily test for 50 or even all 100 variants, including some synthetic cannabinoids that can be added to products to increase potency."

Noestheden says his method was designed to be rolled out in labs around the world. Having worked with Rob O'Brien, president of Supra Research and Development, a cannabis testing lab and industry partner of this study, Noestheden now hopes his new method can be put straight to good use by helping researchers connect variation in phytocannabinoids with the pharmacological effects of various cannabis products.

"It's an elegant solution because any cannabis testing lab with the appropriate instrumentation should be able to adopt the new method with minimal additional investment, making the whole process cheaper and faster."

The study was published in the journal Phytochemical Analysis with funding from MITACS, the University Graduate Fellowship and the Walter C. Sumner Memorial Fellowship.

https://www.sciencedaily.com/releases/2018/05/180517102254.htm