We’re One Step Closer to a Marijuana Breathalyzer
What does Mary Jane’s breath smell like? Inquiring scientific minds are about to find out.
A recent breakthrough has pushed potential manufacturers one step closer to the creation of a marijuana breathalyzer. And, surprisingly, it works by measuring the vapor pressure of THC (the high-inducing ingredient in marijuana).
The Challenges of Design
Tara Lovestead, chemical engineer and one of the brains behind the recent testing development, explains, “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.”
Researchers have never been able to achieve these tests before, mainly because the levels are so difficult to capture. Unlike the ethyl alcohol measured with an alcohol breathalyzer, THC has a complex chemical structure that makes testing a person’s breath much more complicated.
When it comes to marijuana, the major testing hurdles are largely due to THC’s large, complex molecules – specifically the very low vapor pressure the molecules create.
Scientists at the National Institute of Standards and Technology were up to the challenge. Using a new technology called PLOT-cryo, researchers were able to capture and analyze THC molecules in the vapor phase.
How Will This Test Improve Driver Safety?
Why is this a big deal, you ask? With marijuana now legalized in more than half the states, law enforcement officials are in need of a simple but reliable roadside test for marijuana intoxication. (It’s legal to use recreationally or medicinally, but it’s still illegal to drive under the influence of marijuana – in every state.) Urinalysis and blood work are clearly impractical, and a breathalyzer is the obvious solution. But before scientists overcame this hurdle, such a device wasn’t possible.
The hope now is to move forward on the next steps in creating a marijuana breathalyzer. First and foremost is additional research to understand how breath levels of THC correlate with blood levels. Then, scientists must determine what blood levels of THC would make a person too impaired to drive. Standards must be set for each of these levels, then breathalyzer tools can be developed to measure them.
Tom Bruno, a NIST research chemist and co-author of the study, explained, “Fundamental measurements are the basis of standardization. We’re laying the foundation for the reliable systems of the future.”
With so much work ahead, you probably won’t see a marijuana breathalyzer in the hands of a police officer next week – but the concept is much closer to reality than ever before.
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