Researchers from University of California, Los Angeles (UCLA), have developed a chemical test that could form the basis of a cannabis breathalyzer.
Although no such breathalyzer has yet been made, the researchers claim their test is inexpensive and effective enough to hold promise for future practical devices.
High THC levels
As more US states legalize cannabis, there’s a growing concern that “high drivers” could become a greater danger to the public.
But while alcohol breathalyzers can provide a quick and non-invasive test of a driver’s sobriety, there is currently no such device available to measure THC levels.
Hoping to help address this oversight, UCLA researchers have devised an oxidation process that can detect THC.
“We remove a molecule of hydrogen from THC,” senior author Neil Garg, a professor of chemistry at UCLA, said in a statement. “That is oxidation. This leads to changes in the color of the molecule that can be detected.”
Rather than identifying the THC itself, Garg’s method uses electricity to change the structure of THC, so any molecules present will absorb ultraviolet light at a different, detectable wavelength.
“We realized the simplest solution is to pump electricity into THC and have a chemical reaction occur that produces a change we can detect,” Garg continued. “It doesn't matter what the change is, as long as it is easy to detect.”
But although effective, the UCLA test, in its current form, requires several scientific instruments to carry out. A breathalyzer carried by roadside officers would necessitate a much more portable setup.
Garg and his colleagues hope to develop such a device with the help of a private company.
“We want a simple breathalyzer that doesn't require specialized training, because a police officer is not a trained synthetic organic chemist,” Evan Darzi, a former postdoctoral scholar in Garg's lab, said in a statement.
Better than breath
At the moment, the standard method for detecting THC present in a person’s body is to take a blood test. But the tests are invasive and time-consuming.
Several research groups have formed to create a more portable solution. One breathalyzer prototype, developed last year at the University of Pittsburgh, uses carbon nanotubes, 100,000 times smaller than a human hair, to “detect THC at levels comparable to or better than mass spectrometry.”
But other scientists aren’t as convinced that human breath is the best sample to take for THC identification.
According to Shalini Prasad, a professor of bioengineering at the University of Texas at Dallas, the actual THC levels present in breath are so low that such tests risk producing error-prone data, which require extensive processing to filter out other compounds. Saliva, according to Prasad, is a medium far better suited to studying THC intoxication levels, which is why her research team chose to develop their own saliva-based THC detection kit.
“We used the antibody so that we could really only look at the needle in the haystack,” Prasad said in a statement this March. “This is the first demonstration of a prototype device that can report both low and high concentrations of THC in a non-invasive, highly sensitive and specific manner.”