AUG 11, 2018 9:00 AM PDT

Marijuana Breathalyzer Development

WRITTEN BY: Amanda Kahl

Scientists have been working towards creating a marijuana breathalyzer, allowing authorities to determine cognitive and behavioral impairment. Delta-9-tetrahydrocannabinol (THC) is a large molecule with a complex structure compared to ethyl alcohol, making the development of a product like this very challenging. The goal is to measure the vapor pressure of THC.

With the legalization of recreational and medical marijuana in 30 states, authorities are trying to keep the public safe and prevent people from driving under the influence of marijuana. To be able to enforce this, a roadside test for marijuana intoxication needs to be implemented.

Scientists at the National Institute if Standards and Technology (NIST) have discovered how to measure a fundamental physical property in marijuana. A chemical engineer from NIST explains how this can be accomplished, “Vapor pressure describes how a compound behaves when it transitions from a liquid to a gas. That’s what happens in your lungs when a molecule leaves the blood to be exhaled in your breath. So if you want to accurately measure blood levels based on breath, you need to know the vapor pressure.”

Compounds with high vapor pressure such as ethyl alcohol, constantly escape into the vapor phase, while compounds with low vapor pressure such as THC that have large complex molecules, escape slowly. A new technique had to be created to apply technology that can measure the vapor pressure and have a quick and accurate response. It’s called PLOT-cryo (Porous layer open tubular cryogenic absorption). This technology was invented in 2009 to use with airport puffer machines. This highly sensitive machine can capture and analyze the few molecules of THC that do escape into the vapor phase.

Along with being able to measure THC, it can capture the compound cannabidiol. The study was performed by, “sweeping an inert gas across the sample of pure THC to capture escaping molecules, then chilled the gas to collect them (that’s where the ‘cyro’ part of the name comes from). By measuring the mass of the recovered molecules in a known volume and temperature of sweep gas, the researchers calculated the vapor pressure.”

Scientists need to look at multiple variables while conducting research, for example, how do the levels of THC impact people when its consumed or inhaled. Another challenge they face is that THC leaves the bloodstream quicker than alcohol, the impairment of the user last several hours longer than THC concentrations stay in the blood stream. It also accumulates in the tissues; the slow release can show positive in a test several weeks later. Marilyn Huestis from the National Institute on Drug Abuse states, “…on average in the United States it takes from 1.4-4 hours after a crash or traffic stop to administer a blood test. If someone is driving impaired, by the time you get their blood samples, you’ve lost 90% or more of the drug.” This is also posing a problem with how quick THC can leave the bloodstream. Changing the test performed at the roadside when the individual is most impaired could make a difference in keeping the public safe and impaired drivers off the road. 

Further research needs to be conducted to understand how breath levels of THC correlate with blood levels, and how that correlates to levels of impairment. Along with the possibility of creating a device to assist authorities, they also need to be trained on how to identify behavioral signs of impairment.

Sources: Science Daily NIST StudyScience Daily Cell Press

About the Author
  • Amanda has a Bachelor's in Biological Sciences from the University of Cincinnati. She has a passion for animals, conservation, and environmental sciences. Through her career in science and research, she is able to develop her passion and hopes to pass on to others the joy of learning about science.
You May Also Like
AUG 10, 2020
Cannabis Sciences
Cannabis Use During Pregnancy Linked to Autism
AUG 10, 2020
Cannabis Use During Pregnancy Linked to Autism
Researchers from The Ottawa Hospital in Ontario, Canada, have found that children born to mothers who used cannabis whil ...
AUG 12, 2020
Health & Medicine
Boomers Use Cannabis Mostly for Ailments; Millennials for Recreation
AUG 12, 2020
Boomers Use Cannabis Mostly for Ailments; Millennials for Recreation
A survey by marijuana dispensary chain Verilife has found that older and younger cannabis consumers have very different ...
SEP 23, 2020
Cannabis Sciences
Hemp Seeds May Reduce Heart Disease Risk
SEP 23, 2020
Hemp Seeds May Reduce Heart Disease Risk
Heart disease is the leading cause of death around the world. And it seems that many methods to avoid it involve lifesty ...
NOV 01, 2020
Cannabis Sciences
Can Cannabis Treat ALS?
NOV 01, 2020
Can Cannabis Treat ALS?
Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative illness that damages motor neurons and leads to progressive m ...
NOV 23, 2020
Health & Medicine
Federal Report Shows Teen Marijuana Treatment Admissions Have Been Falling
NOV 23, 2020
Federal Report Shows Teen Marijuana Treatment Admissions Have Been Falling
Concerns that the legalization of recreational marijuana might cause an upswing in young people misusing the drug have b ...
DEC 15, 2020
Cannabis Sciences
Could Cannabis Help in the Opioid Crisis?
DEC 15, 2020
Could Cannabis Help in the Opioid Crisis?
While cannabis is increasingly available for medicinal use, doctors largely remain unable to prescribe it to their patie ...
Loading Comments...