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.
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.
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