Federally Funded Researchers Discover Two New Methods Of Distinguishing Hemp And Marijuana To Assist Crime Labs

Federally funded researchers have identified new methods of distinguishing between marijuana and hemp by detecting the exact amount of THC in flower and edibles.

The National Institute of Justice (NIJ), which is part of the Justice Department, is promoting the results of two research projects it funded focused on cannabis lab testing, which it is now sharing with select law enforcement agencies.

The aim of the initiatives was to streamline the testing process to help resolve crime lab backlogs that have increased since hemp containing up to 0.3 percent THC was federally legalized under the 2018 Farm Bill, complicating cannabis-related cases.

Current testing methods aren’t able to “measure the exact amount of THC present in a sample,” NIJ said in a update posted on Tuesday. But the researchers they funded have now discovered that they can isolate the THC content, as well as other cannabinoids, using two different types of mass spectrometry: gas chromatography-mass spectrometry (GC-MS) and direct analysis in real time-high-resolution mass spectrometry (DART-HRMS).

The GC-MS method was developed by a team at the National Institute of Standards and Technology (NIST). They were able to extract THC from a sample and apply the test to find the exact cannabinoid content. DOJ first announced in 2020 that it would be granting NIST $350,000 in funding for the research.

The DART-HRMS tactic, meanwhile, could help to address another cannabis testing complication that’s emerged in forensic labs. It allowed researchers to determine the amount of THC present in “baked goods, candies, beverages, and plant materials with minimal pre-treatment steps.”

Rabi Musah, the lead research with the DART-HRMS team, “anticipates that the increased speed of using DART-HRMS to detect THC in cannabis samples could reduce sample testing backlogs and chemical reagent costs and streamline sample analysis protocols,” NIJ said.

NIST’s GC-MS method has already led to the creation of new standard operating procedures for labs, and the results have been incorporated into training practices for the Montgomery County Police Department and Maryland State Police.

U.S. Customs and Border Protection (CBP) also put out a solicitation in 2022, seeking portable marijuana analyzers to quickly identify cannabinoid profiles and help distinguish between marijuana and hemp.

The Drug Enforcement Administration (DEA) separately announced in 2019 that it was seeking a device to “provide specificity to distinguish between hemp and marijuana” since the former crop was legalized.

The complications resulting from hemp legalization became especially apparent in Texas, where marijuana possession arrests fell almost 30 percent from 2018 to 2019 following the state-level legalization of the non-intoxicating cannabis crop. Prosecutors in the state dismissed hundreds of low-level cannabis cases since hemp was legalized. And officials announced in 2020 that labs wouldn’t be performing testing in misdemeanor cases, with the Department of Public Safety saying it “will not have the capacity to accept those.”

Meanwhile, hemp industry stakeholders and agriculture officials across the U.S. are urging Congress to triple the THC limit for the crop to one percent by dry weight. A Justice Department researcher recently questioned the rationale for the current 0.3 percent THC limit, which she said seemed to be based arbitrarily on a decades-old anecdote.

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Photo courtesy of Brendan Cleak.