New alcohol test targets sweat
Sensing strip being developed with law enforcement in mind
Sweat might have a lot more practical uses than just helping keep the body cool.
It could also one day be used by law enforcement agencies in the fight against drunken driving.
A prototy pe sensing strip that can detect a person’s bloodalcohol content based on ethanol levels in a small sweat sample is being tested at a University at Albany lab, according to Jan Halámek, an assistant professor of chemistry, and Mindy Hair, the lead graduate assistant on the project.
“The strip which we have now is a very preliminary design, so we work on that to be even more stable and precise,” Halámek said.
Halámek said sweat glands are close enough to the bloodstream that ethanol can be transferred between the two f luids. The strips work similarly to pregnancy tests or glucometers. When the strip is placed on the skin, traces of ethanol produce a color spot. The darker the spot, the more alcohol in the system, the researchers said.
The strips are being studied at the Halámek Lab.
Two years ago, Halámek’s team studied a system that would allow sweat-based authentication to unlock smartphones and wearable electronic devices.
Halámek hopes to team up with the university ’s police department to field-test the strips along with the Breathalyzers that police officers at the school — and around the country — use to measure the level of alcohol in drivers’ bodies.
“Do I have the final design of the device? No,” said Halámek, a native of the Czech Republic. “My ultimate goal here is to [develop] a field kit that I can do different compounds — ethanol and other drugs.”
Halámek, a forensic chemist, said the research came about because of the need in law enforcement for another noninvasive way to test if a person is drunk. “We test our system versus the police
Breathalyzer and the results are very similar,” he said.
He also said the strips could become alternatives to the devices police use for alcohol breath tests, which can have f laws. Diabetics can have acetone not connected to alcohol consumption on their breaths. Mouthwashes and even vapors from windshield wiper f luid can inf late blood-alcohol readings.
Halámek teams used a controlled study to test the effectiveness of the strips. The examination of tests done on the 26 volunteers confirmed the results were in line with testing by Breathalyzers.
The testing was complex, with the first sweat sample taken when the test subjects were sober. The subjects then consumed vodka, and the scientists relied on the use of a small electric current to stimulate the sweat glands, Hair said. She said each test took roughly 30 minutes.
“Depending on how much they were up for it, they took three or four shots of a 40-proof vodka,” Hair said. “I asked them to take them as quick as possible so it all absorbed at the same time, and they were allowed a chaser.”
After that, a Breathalyzer reading was taken every 10 minutes. Once the alcohol stabilized, a second sweat sample was taken. “We repeated that process as they started going down and down in BAC until they got to sobriety again,” she said, adding they were able to collect multiple sweat samples at various blood-alcohol levels from each test subject.
More than 100 readings were compared between a Breathalyzer and the sensing strip.
“We were able to correlate the Breathalyzer responses to the sweat responses,” she added. “As you increase your BAC, you were getting more ethanol in sweat.”
Legally, police can charge someone with driving while ability impaired if their blood-alcohol content is between 0.05 percent and 0.07 percent. Drivers can be charged with driving while intoxicated once the blood-alcohol content crosses the 0.08 percent mark.
The findings were published in Analytical Chemistry, a peer-reviewed research journal.
Hair said a computer science undergraduate is helping the team develop a smartphone app to match the test strip’s color change with BAC level to avoid any discrepancies. Hair, who graduates in May, is hoping to test the app sometime this month or next.