How Breathalyzers Work
(and Why They Don't)
Information courtesy of Lawrence Taylor - DUIblog
Did you ever wonder how breathalyzers work? There is a website which will give you a pretty fair idea. But first, let's clear up some confusion....
There are many different kinds of "breathalyzers" -- or, more accurately, there are many kinds of breath testing devices. The first of the modern breath testers, manufactured by Smith and Wesson many years ago (yes, that Smith and Wesson), was called the Breathalyzer. Since then, various manufacturers have recognized the growing market and come out with their own models, bearing such names as Intoxilyzer, Intoximeter, DataMaster, AlcoSensor, Alcotest and so on; most of these products have been produced in different model versions, such as the Intoxilyer 4011, 5000 and 8000. To deal with the confusion, the term "breathalyzer" came to be used as a generic term for any breath testing instrument. (To confuse things further, a German company -- Draeger -- bought the rights to the Breathalyzer brand and have sometimes used that name in some of their models.)
Most of these are evidentiary machines -- that is, larger machines generally kept at the station whose test results are used in evidence. Others are smaller, handheld units carried by officers in the field; these are less accurate, and are usually used as a field sobriety test to help determine whether to arrest a suspect.
The original Breathalyzer operated using a wet chemical method of analysis, employing a disposable glass ampoule of chemicals. Although still occasionally found in law enforcement, this relatively primitive technology was replaced in later machines by infrared spectroscopy, gas chromatography or, mainly in handheld units, fuel cell analysis; a couple of the more recent machines use a combination of infrared and fuel cell.