R&D Success Stories / Laser Sensing of Ethanol Vapor and Liquid: Non-Invasive, Unobtrusive Remote Sensing of Ethanol

Vapor chart: water and ethanol/water mixture

At SESI, we are exploring the feasibility and practicality of laser sensors for non-invasive, unobtrusive detection of ethanol (ethyl alcohol) in both vapor phase and liquid form (i.e., condensed phase).

The work being done on these laser sensors is sponsored research and developed under contract to the National Institute of Alcoholism and Alcohol Abuse (NIAAA) at the National Institutes of Health. Human blood alcohol (ethanol) content is the standard by which our sensor development efforts in the Program will ultimately be judged. We must provide an EtOH (ethyl alcohol) sensor which is sensitive to as little as 5 mg per dl of blood alcohol content, and do so with an external (i.e., non-invasive) sensor and furthermore an unobtrusive sensor.

That is a sensor whose presence does not disturb the human or animal subject of alcohol consumption and/or treatment studies. Our research in bio-sensing with low-power laser radiation has led us to believe that laser diode-based sensor technology can indeed be developed for measuring the very low concentration of ethanol vapor in human or animal expelled breath with a lidar instrument that operates on a free-atmospheric path in a laboratory test environment.

Furthermore this same laser diode technology when coupled to fiber optic probes can be used to measure ethanol content in human and animal tissue even when the probes are located external to the skin surface. For this project we are teamed with researchers at the University of Kentucky, College of Pharmacy, Lexington, Kentucky who bring the ability to conduct human and animal studies as well as provide special chemometric analysis capability to our laser data and offer the additional possibility of remote imaging of alcohol content in human and animal tissue through molecular factor computing.

Both our vapor phase and condensed phase ethanol studies and the work at the University of Kentucky are focusing on the use of invisible, near-infrared radiation in the 900 nm to 3500 nm region of the optical spectrum.