On what scientific principle does the Intoxilyzer 9000 operate?

The Intoxilyzer 9000 operates based on the principle of infrared spectrometry, which is a method that involves measuring the absorption of infrared light by vaporized samples of breath. When a subject exhales into the device, the breath sample contains alcohol and other components. The infrared light passes through this sample, and specific wavelengths of light are absorbed by alcohol molecules due to their unique molecular structure.

The device measures the intensity of light that is transmitted through the breath sample and calculates the concentration of alcohol based on the amount of light absorbed. This quantitative analysis ensures that the results correlate to the blood alcohol content in a person's system, making it a reliable tool for assessing impairment due to alcohol consumption.

Gas chromatography, mass spectrometry, and ultraviolet spectrometry are valid scientific methods for analyzing substances but are not the foundational principles used by the Intoxilyzer 9000. Gas chromatography typically separates compounds in a mixture before measurement. Mass spectrometry identifies compounds based on their molecular weight, while ultraviolet spectrometry measures absorbance in the ultraviolet range but is not utilized in this particular device. This understanding of the operating principle is crucial for those involved in the oversight or use of alcohol breath testing technologies.