Optoelectronic Noses Uncover Counterfeit Liquors

With the alcoholic beverage market booming in the U.S., the safety and quality of both domestic and imported products must be assured. A disposable sensor that detects adulteration of liquor has been developed by researchers at the University of Illinois at Urbana-Champaign. The device is handheld and can be used quickly in the field to identify tampered or watered down spirits.

The colorimetric sensor array with 36 dyes can quickly categorize 14 liquors by alcoholic content and brand name, with an accuracy rate higher than 99 percent, according to the research published online ahead of print in ACS Sensors. These optoelectronic noses are designed to probe a broad range of chemical interactions by using a set of chemo-responsive dyes immobilized in relatively hydrophobic matrices. The sensor changes color when exposed to particular components in liquor, and it can detect liquor that has been watered down by as little as 1 percent.

“The device is a digital, multidimensional extension of litmus paper,” says researcher Kenneth S. Suslick, PhD, Marvin T. Schmidt Research Professor of Chemistry at University of Illinois at Urbana-Champaign. ”We use an array of chemically responsive dyes (like the dyes in litmus or pH paper or even black tea when lemon is added), and it is the pattern of their color changes after exposure to a vapor that tells the identity of the vapor being sniffed.”

The portable and self-contained device developed by Dr. Suslick and colleagues could potentially be used “in rick houses where barrels are aged or even in local bars to keep the barkeep honest,” Dr. Suslick said. The technology should be marketable within a year, with the technology being commercialized by iSense LLC, Mountain View, Calif.

The same device with a slightly different array has also been used to monitor meat freshness. In the research published about the device in 2016 in ACS Sensors, it is described as a portable handheld, self-contained optoelectronic nose that allows for in situ and real-time collection of data related to meat spoilage.

Several techniques are being used to detect adulterated whisky and spirits, but these most commonly are used in a lab setting. Another method designed for use in the field is a portable gas chromatography/mass spectrometry device from PerkinElmer that can detect the presence of denatured alcohol that has been added to spirit drinks.