光离子化检测（Photoionization detector，缩写PID），是利用惰性气体真空放电现象所产生的紫外线（VUV），使待测气体分子发生电离，并通过测量离子化后的气体所产生的电流强度，从而得到待测气体浓度。

光离子化检测技术作为一种精确而有效的检测手段，在今天获得了越来越广泛的应用。

A photoionization detector or PID is a type of gas detector.

Typical photoionization detectors measure volatile organic compounds and other gases in concentrations from sub parts per billion to 10 000 parts per million (ppm). The photoionization detector is an efficient and inexpensive detector for many gas and vapor analytes. PIDs produce instantaneous readings, operate continuously, and are commonly used as detectors for gas chromatography or as hand-held portable instruments. Hand-held, battery-operated versions are widely used in military, industrial, and confined working facilities for health and safety. Their primary use is for monitoring possible worker exposure to volatile organic compounds (VOCs) such as solvents, fuels, degreasers, plastics & their precursors, heat transfer fluids, lubricants, etc. during manufacturing processes and waste handling.