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Ion Science Ltd is an international manufacturer of volatile organic compound detection, organic compound detection and volatile organic compound monitoring equipment. Their instruments are conceived and designed by a talented in house team to meet the needs of a wide range of industries and applications. Research is at the heart of this company and is fundamental to their technology and product development.

Ion Science Volatile Organic Compound Detection Instruments Work Better in High Humidity!

How PID Works: Phocheck+ measures volatile organic compounds in air by photoionisation detection (PID), which is shown schematically in the figure below. Test gas (1) is drawn into the chamber from the Phocheck+ probe. It is caused by the chamber design to move across the face of a lamp window, emitting light particles, or photons (shown by arrows) of high UV energy. Essential for the detection of a molecule XY is photoionisation (2), which occurs when a photon, is adsorbed (2a) by the molecule, generating two electrically charged fragments, or ions, (2b), one positively charged, X+, and one negatively charged, Y-. An electric field between two metal grids, called electrodes, attracts ions towards them. At the electrodes, ions are neutralised by movement of a tiny electric current, the photoionisation current, which is proportional to the concentration of XY, so that it can be amplified and displayed as a gas concentration. Phocheck+ contains a third, fence electrode, patent pending, to ensure that the amplified current does not include a significant current due to other causes, such as water condensation on the chamber walls. Exhaust gas (3) is removed from the chamber by means of a pump inside the Phocheck+ housing. Call 1-800-739-7706 for product sales.