How do breath tests detect alcohol levels in blood?
Here is how the breathalyzer web site answers the question: Most breathalyzers use one of three technologies to detect alcohol: a spectrophotometer, a fuel-cell sensor or a semiconductor oxide sensor. Spectrophotometer technology is used in large, table-top breathalyzers often found at police stations. Spectrophotometers work by identifying molecules based on the way they absorb infrared light. The level of ethanol in a sample is singled out and measured, and a subject’s alcohol level can then be determined. Breathalyzer.net does not carry spectrophotometer testers. Fuel-cell testers, such as the Lifeloc FC series, offer extremely high accuracy and sensitivity, in addition to being handheld and portable. In over 30 US states, roadside evidential testing is now permitted using testers like these. A fuel cell measures alcohol content by creating a chemical reaction that oxidizes the alcohol in the sample and produces an electrical current. The more alcohol that is oxidized, the greater t
