Opal-Based Breathalyzer Being Developed
October 9, 2013

New Breathalyzer Technology Could Offer Cheaper, More Precise Way To Catch Drunk Drivers

redOrbit Staff & Wire Reports - Your Universe Online

A team of Italian researchers are hoping to make catching drunk drivers easier and less expensive for police officers by developing a new portable breathalyzer capable of testing for precise alcohol concentrations.

Their research, which appears in Tuesday’s edition of The Optical Society's (OSA) journal Optical Materials Express, describes a new portable device that would change colors from green to red when it detected higher levels of alcohol. Unlike the color-changing devices currently available, however, this unit would reportedly be reusable and would provide an exact digital readout.

According to the OSA article, the breathalyzer is currently in its proof-of-concept stage. However, it would be the first device of its kind to use the sensing properties of the gemstone opal to detect the gas version of ethanol (the component of commercial liquor that causes intoxication) by inducing a change in color that is visible to the human eye.

“The portable breathalyzers preferred by roadside police use expensive electronic readouts, but these devices lack the ‘immediate and intuitive’ color change that tells police whether the alcohol content of a suspect's breath puts them in the legal red zone,” the organization said in a statement.

“Techniques that do use color change to assess the level of alcohol concentration are typically less expensive, but they cannot give a precise reading of the alcohol concentration and most are use-once-and-toss,” the researchers added. The new unit, designed by Riccardo Pernice of the Università degli Studi di Palermo in Italy and his colleagues, combines the best features from both devices.

Pernice explained that his team’s device features optical detection that changes color, from green to red, not unlike the litmus paper used by scientists to determine whether a solution is acidic or basic. However, their breathalyzer also allows for “accurate quantitative measurements” through the addition of an electronic system or a color detector. The concept was inspired by the natural light-manipulation properties of opals.

Scientists use manufactured versions of photonic crystals such as opals to detect the presence of liquid ethanol, but the researchers said that the gaseous form of ethanol had been largely ignored. Pernice’s team created sheets of manufactured opal, approximately one centimeter square and only a few hundred-billionths of a meter thick. The opals were pumped full of a gel that had been specially calibrated to respond to ethanol vapor.

“At increasing ethanol concentrations, the gel swells, changing the way light travels through the gel-filled opal and causing the sample to become red,” the OSA explained. “The change in color is clearly visible to the naked eye… and the device is usable multiple times. After performing the measurements, researchers found that the sample gradually regained its original green color after less than one minute of exposure in air.”

The investigators added that the sensor poses no risk to the environment once it is disposed of, because it is made from 100-percent non-toxic materials. Furthermore, Pernice said that it does not react to acetone (a substance that can lead to false-positive readings in breathalyzers) and is currently capable of detecting much higher concentrations of alcohol than other portable sensors. They also hope to test its effectiveness at lower concentrations in the near future.