Fixed Point and Portable Detectors for Volatile Organic Compounds (VOC) Monitoring


A photo ionization detector (PID) measure volatile organic compounds VOC and other toxic gases in low concentration from part per billion up to 10,000 part per million or 1% by volume. A PID is a very sensitive broad spectrum monitor. All elements and chemicals can be ionized, but they differ in the amount of energy they require. The energy required to displace an electron and ionize a compound is called its Ionization Potential or IP, measured in electron volts (eV). The light energy emitted by an UV lamp is also measured in eV. If the IP of the sample gas is less than the eV output of the lamp, then the sample gas will be ionized. (reprinted from AP from Rae Systems).