Chocolate muddles cannabis potency testing
AMERICAN CHEMICAL SOCIETY
SAN DIEGO, Aug. 25, 2019 — 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. ACS, the world’s largest scientific society, is holding the meeting here through Thursday. It features more than 9,500 presentations on a wide range of science topics.
“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.”
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 Î”9-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.