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Marijuana Breathalyzers - How Does It Work?


A UCLA chemist and colleagues have made progress toward their goal of developing a portable device that can detect THC on a person's breath after marijuana use, similar to an alcohol Breathalyzer. It is called aMarijuana Breathalyzers.

Neil Garg, a professor of natural chemistry at UCLA, and researchers from the university's startup ElectraTect Inc. describe how THC introduced into their laboratory-built machine in a solution can be oxidized, producing an electrical present whose strength indicates how much of the psychoactive substance is present.

According to the researchers, since marijuana has been decriminalized or legalized in several places, including California, having a device similar to a Breathalyzer available could help improve road safety. Research has shown that marijuana use affects some driving skills and is linked to a significantly increased risk of accidents.

How Do The Marijuana Breathalyzers Work?

A police holding a marijuana breathalyzer
A police holding a marijuana breathalyzer

Darzi, who is currently the CEO of ElectraTect, Garg, and researchers from ElectraTect describe the operation of their brand-new laboratory-scale THC-powered fuel cell sensor in the new study.

THC (technically known as Delta-9-tetrahydrocannabinol) oxidizes into a new compound called THCQ when it comes into contact with a negatively charged electrode, or anode, on one side of the device's H-shaped glass chamber, sending electrons across the chamber to a positively charged electrode, or cathode, on the other, creating a detectable electric current.

The current becomes stronger as the amount of THC molecules increases. THC has never before been utilized to operate a fuel cell sensor, so this development is significant.

Researchers are currently working to refine the device to detect and measure THC in exhaled breath and to shrink it to a more compact size suitable for use in a handheld breath analyzer or ignition interlock device, a breath analyzer connected to a vehicle's ignition that prevents it from starting if THC is detected.

The researchers said they expect that the relatively simple, inexpensive technology, once perfected, can be scaled up for economical mass production.

Marijuana Breathalyzers Are Becoming A Reality

Determining impairment in relation to alcohol is not a difficult task. Water-soluble alcohol spreads swiftly throughout the body and is eliminated in a matter of hours because humans are approximately 60% water.

A simple ratio connects the amount of alcohol in a person's breath to the amount in their blood, and if you drive with a blood-alcohol concentration (BAC) over the legal limit, you run a good risk of getting pulled over by the police.

A breathalyzer can identify the THC that is transported from the bloodstream and into the lungs for the first few hours after smoking a joint or eating an edible, just like it can for alcohol.

But after that, THC is changed into metabolites, which are non-psychoactive chemicals. THC breaks down into more than 80 different metabolites, many of which are stored in fat.

The amount of time these metabolites stay in the body depends on a number of variables, including gender, level of tolerance, percentage of body fat, and the manner and type of cannabis consumed.

According to California-based Hound Labs, current tests that look for metabolites instead of THC can't tell apart between someone who smoked cannabis lawfully and responsibly at a BBQ on Friday night from their coworker who smoked Monday morning on the way to work.

According to CEO Mike Lynn, the company's Hound Marijuana Breathalyzer is one billion times more sensitive than an alcohol breathalyzer and will begin shipping to potential clients towards the end of this year.

It Makes Marijuana Testing Easier

The technology may also result in increased road safety and more equitable marijuana law enforcement, according to the researchers. THC usage in drivers is typically detected through urine or blood tests.

Such roadside tests can be challenging to do, and they aren't always reliable for detecting intoxicated drivers because the chemical can persist in the body for weeks after marijuana use without having any lasting impact on cognition.

These problems, according to the researchers, emphasize the requirement for cutting-edge forensic technology that is simpler to use and more precise for identifying recent marijuana use.

Although a commercial marijuana breathalyzer based on their research would be a few years away, Darzi and Garg emphasized that such a device would potentially offer advantages beyond those of law enforcement and traffic safety.

They claimed that their scientific advance might ultimately be applied to any circumstance where impartial marijuana testing is necessary, including in the workplace where workers might be running machinery or even at home where people would one day be able to use it proactively.


So, where else could THC marijuana breathalyzers be used if not on the side of the road? In the workplace, according to some marijuana enthusiasts. In fact, the group is actively working to pass legislation that would make it illegal for California companies to treat applicants differently based on their history of cannabis use.

Gieringer contends that it makes more sense and is less invasive to require a worker to blow into a THC breathalyzer prior to performing certain tasks, such as operating heavy machinery or flying an airplane.

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About The Authors

Dr. Bill Butcher

Dr. Bill Butcher- With more than two decades of experience, Dr. Bill Butcher aims to provide a repository for educational materials, sources of information, details of forthcoming events, and original articles related to the medical field and about health subjects that matter to you. His goal is to help make your life better, to help you find your way when faced with healthcare decisions, and to help you feel better about your health and that of your family. Bill received his medical degree at Boston University School of Medicine and spent his entire career helping people find the health and medical information, support, and services they need. His mission is to help millions of people feel fantastic by restoring them to optimal health.

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