Researchers develop the chemistry necessary to create marijuana breathalyzer

UCLA chemists have reported on the key chemical discovery necessary for the creation of a small electronic marijuana breathalyzer. The research is published in Organic Letters, a peer-reviewed journal of the American Chemical Society.

The legalization and decriminalization of marijuana in California and elsewhere has made marijuana screening especially important, said lead author Neil Garg, UCLA professor of chemistry and biochemistry Kenneth N. Trueblood and chairman of the department of chemistry and biochemistry at UCLA.

“When I grew up, people were taught not to drive drunk,” said Garg. “I still haven’t seen the same type of messages for marijuana, and statistics indicate that more than 14 million people in the United States smoke marijuana and drive. Our goal was to come up with a very simple solution that could be adopted by society. We have demonstrated in this study that we can change the chemical structure and properties of THC, the primary psychoactive ingredient in marijuana, using perhaps the simplest chemical means possible – electricity, to determine if a person is affected. “

“We want a simple breathalyzer that does not require specialized training because a police officer is not a trained synthetic organic chemist,” said lead author Evan Darzi, a former postdoctoral scholar in Garg’s lab.

While Darzi and Garg have developed the chemistry that would be at the heart of a marijuana breathalyzer, they have not created a real device. “We have established the fundamental proof of concept,” said Garg, who received the 2018 Robert Foster Cherry Award, which is the largest university teaching award in the US. Awarded by Baylor University and named California Professor of the Year 2015.

Darzi and Garg developed a simple oxidation process similar to that used in an alcohol breathalyzer. Oxidation is the loss of an electron from a molecule. The researchers removed a hydrogen molecule from THC (whose full name is delta-9-tetrahydrocannabinol). Alcohol breathalyzers convert ethanol into an organic chemical compound, and hydrogen is lost through the oxidation process.

“The chemistry we are doing with THC is the same,” said Garg. “We remove a hydrogen molecule from THC. That is oxidation. This leads to detectable changes in the color of the molecule.”

Darzi and Garg report two ways to oxidize THC. Her preferred and inexpensive approach is to use electricity.

“Some of our initial ideas involved trying to get complicated molecules to bind to THC to detect a signal,” Garg said. “After a while, we realized that the simplest solution is to pump electricity to THC and for a chemical reaction to occur that produces a change that we can detect. No matter what the change is, as long as it is easy to detect. Oxidation is one of the simplest reactions one can make to a molecule. “

THC’s structure includes a unit called phenol. When chemicals oxidize a phenol, the oxidation produces a member of a class of organic compounds called quinones. “We know how to oxidize a phenol into a quinone,” said Garg.

THC and quinone absorb light differently. “Once we knew that,” said Garg, “we decided to use electricity to perform the oxidation.” Darzi used a new device in Garg’s lab (called ElectraSyn 2.0 by IKA Works) that allows him to perform electrochemical reactions.

Chemists saw a change in where the molecules absorb light. THC absorbs light at a certain wavelength, and Darzi and Garg discovered that when it oxidizes, it absorbs light at a different wavelength.

“Doing organic chemistry using electrochemistry is not something that people in my field have historically done regularly,” Garg said. “Evan studied different variations of how to set up chemical reactions until he found the best way to oxidize THC.”

To conduct the research, the chemists first obtained a license from the US Drug Control Administration. USA To study THC in your laboratory.

The chemists said they have had positive responses from other chemists with whom they have shared their research.

The next big step, Garg said, is to achieve the same result with a breath sample from a person who has recently used marijuana and avoid false positives. Studies suggest that marijuana in breath can reliably reveal whether marijuana has been smoked or consumed in the past four to five hours, Darzi said. Garg hopes his laboratory will continue this research in collaboration with a company interested in developing the technology. However, he noted that there are significant challenges to developing this technology at a university due to federal regulations. UCLA has filed a provisional patent application on the oxidation of THC.

Garg’s hope is that a marijuana breathalyzer is inexpensive enough for consumers to buy so they can test themselves before deciding whether to drive. Garg and Darzi hope that a marijuana breathalyzer will produce a numerical result, perhaps similar to a breathalyzer’s blood alcohol level measurements, but the details are beyond the scope of this research.

“Professor Garg and I have young children,” said Darzi, “and our children will grow up in a world where marijuana is legal. We are happy to be able to help society address this problem.”