Breath Alcohol Tests – QCLs Improve Accuracy

Researchers have developed a new way of operating miniature quantum cascade lasers (QCLs) to rapidly measure the absorption spectra of different organic molecules in the air simultaneously. The technique offers a sensitive method for detecting low concentrations of volatile organic compounds (VOCs), improving the ability to track how these compounds affect human health, industrial processes, and ambient air quality. The new system also could improve the reliability of breath alcohol tests by more selectively distinguishing between ethanol and the other gases people exhale.

The researchers designed a QCL-based setup that measures compounds absorbing electromagnetic radiation across a wide spectrum with a single laser, a task that would have previously required multiple lasers working together.

VOCs are commonly found in vehicle exhaust, solvents, building materials, and many other products. They can be harmful to people and ecosystems, and they contribute to tropospheric ozone production and to global warming. Real-time methods to identify and track VOCs are important for pollution and climate researchers, public health organizations (breath alcohol tests), manufacturers, first responders, and shippers, among others.

The new system, based on an electrically tunable infrared laser with no mechanical parts, provides sufficient precision and scans a wide enough range of optical frequencies to simultaneously identify several species that are present and determine their concentrations.

Read more