29-10-2008, 11:18pm
Modern breathalyzers work on a clever electrochemical principle. The subject's breath is passed over a platinum electrode, which causes the alcohol to bind with oxygen, forming acetic acid. In the process it loses two electrons, a process that sets up a current in a wire connected to the electrode. The higher the concentration of alcohol in the breath, the greater the electrical current, which can be read by a simple meter to indicate intoxication levels.