Law enforcement has long been struggling to come up with a device that can accurately measure marijuana intoxication in the field.
While testing for alcohol levels is as simple as having a person blow into a breathalyzer, deciphering marijuana’s influence is far more complex.
Now, scientists may be closer to a solution.
Researchers from the University of Pittsburgh have unveiled a breathalyzer device they say can measure levels of THC – weed’s dominant psychoactive compound – in the breath.
While testing for alcohol levels is as simple as having a person blow into a breathalyzer, deciphering marijuana’s influence is far more complex. Now, scientists may be closer to a solution. Stock image
Currently, testing for marijuana levels is done using blood, urine or hair samples. But, this doesn’t tell much about whether a person is currently under the influence.
The new device uses carbon nanotubes, which bind with the THC molecules to detect the compound with a higher degree of precision.
‘The semiconductor carbon nanotubes that we are using weren’t available even a few years ago,’ says lead author Sean Hwang.
‘We used machine learning to “teach” the breathalyzer to recognize the presence of THB based on the electrical currents’ recovery time, even when there are other substances, like alcohol, present in the breath.’
According to the team, the system is about as good – or possibly better – than mass spectrometry, which is right now considered to be the best method of THC detection.
The prototype looks much like a standard breathalyzer, and tests showed it could not only detect THC in the breath, but distinguish it from compounds such as carbon dioxide, water, ethanol, methanol, and acetone.
‘Creating a prototype that would work in the field was a crucial step in making this technology applicable,’ says Ervin Sejdic, PhD.
The prototype looks much like a standard breathalyzer, and tests showed it could not only detect THC in the breath, but distinguish it from compounds such as carbon dioxide, water, ethanol, methanol, and acetone. Above, the researchers are shown holding their device
‘It took a cross-disciplinary team to turn this idea into a usable device that’s vital for keeping the roads safe.’
While it isn’t a perfect system yet, the researchers say it’s a step in the right direction.
‘In legal states, you’ll see road signs that say “Drive High, Get a DUI,” but there has not been a reliable and practical way to enforce that,’ says Alexander Star, PhD, who leads the Star Lab.
‘There are debates in the legal community about what levels of THC would amount to a DUI, but creating such a device is an important first step toward making sure people don’t partake and drive.’
