Photoionization Detector (PID) is the most frequently used on-site detection instrument for volatile organic compound (VOC) monitoring. PIDs offer the combination of speed of response, ease of use and maintenance, small size, and ability to detect low levels, including most volatile organic compounds (VOCs).

• Working Procedure
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The PID is comprised of an ultraviolet lamp that emits photons that are absorbed by the compound in an ionization chamber. Ions (atoms or molecules that have gained or lost electrons and thus have a net positive or negative charge) produced during this process are collected by electrodes. The current generated provides a measure of the analyte concentration. Because only a small fraction of the analyte molecules are actually ionized, this method is considered nondestructive, allowing it to be used in conjunction with another detector to confirm analytical results. PIDs measure organic compounds such as benzene, toluene and xylene, and also certain inorganics such as ammonia and hydrogen sulfide. As a general rule, if compounds measured or detected contain a carbon (C) atom, a PID can be used. However, such is not always the case, as methane (CH4) and carbon monoxide (Co) cannot be detected with a PID.

The DDI’s well trained technicians will help you to get the most cost effective and accurate results by using PID systems.