Chocolate components could interfere with cannabis activity tests
Cannabis-based edibles, such as gummy bears, cookies and chocolates have flooded the edible market in the legalized states. These sweet treats have created significant headaches for scientists trying to analyze them for potency and contaminants. Researchers report now that chocolate components could interfere with cannabis activity testing, which would lead to inaccurate results.
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Following this discovery, researchers will present their findings to the American Chemical Society (ACS) in the fall 2019. The AE will hold its meeting which will include more 9500 presentations on a wide range of scientific topics.
"My research is focused on cannabis potency testing because of the high stakes associated with it," says David Dawson, Ph.D., the project's lead researcher. "If an edible cannabis product tests 10% below the amount on the label, California law states that it must be relabelled, with considerable time and expense. But it's even worse if a product tests 10% or more above the amount on the label - then the whole lot must be destroyed. "
Manufacturers are adding cannabis to a wide variety of foods, and the composition of these products, also known as the "matrix", can affect the results of activity testing. Dawson and colleagues at CW Analytical Laboratories have decided to focus on activity testing for cannabis infused chocolates because it is a very common product. CW Analytical Laboratories is a cannabis testing laboratory in Oakland, California, where recreational marijuana became legal in 2018. "We also noticed, anecdotally, bizarre power variations depending on how we prepared the chocolate samples for analysis," he says. Dawson therefore investigated the effects of changing sample preparation 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 component 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 would get higher THC concentrations and more accurate values than when we had 2 grams of the same chocolate infused in the vial," says Dawson. "This goes against what I consider to be a basic statistical representation of the samples, where one might assume that the more samples you have, the more representative they are of the whole." These results suggest that another chocolate component (a matrix effect) would suppress the signal for Δ9-THC.
"Simply changing the amount of sample 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 on the client who might be under-dosed. or overdosed because of this weird quirk of matrix effects, "he notes.
Now, Dawson is trying to determine which ingredient in chocolate is responsible for the effects of the matrix. He tried to add a standard solution of Δ9-THC with varying amounts of chocolate bars, cocoa powder, bakery chocolate and white chocolate, all of which have different components, and observe how the signal HPLC changes. "Our best track right now is that it has something to do with fat, which makes sense because Δ9-THC is fat soluble," says Dawson.
The team would like to extend its analysis to other cannabinoids, such as cannabidiol (CBD), a non-psychoactive substance found in many edible products. In addition, they plan to study other food matrices, such as chocolate chip cookies. Dr. Dawson hopes that the research will contribute to the development of standardized methods for evaluating the activity of cannabis in a variety of edible products. "We owe this research to the scientific community, producers and consumers," he says. "We must be able to provide very accurate and precise tests on a wide range of matrices."