Ionization detectors in environmental analysis

Ionization detectors (IDs) use the information contained in the radiation-produced ionization current regarding the chemical composition of gas mixtures. The radionuclide radiation sources, 3H, 55Fe, 63Ni, 85Kr, 90Sr, 241Am, are used to produce carriers. Using recombination effects and carrier multiplication by electrical fields the response of IDs can be improved. There are electron capture detectors, cross-section detectors and noble-gas detectors, mainly used in gas chromatographic devices, and continuously working aerosol ionization detectors. Halocarbons, metal chelates, metal organic and inorganic compounds, pesticides, herbicides, insecticides, but also SO2, AsH3, ClCN, HCN, HF, NH3, CO, CO2, H2O, can be determined within the pp109 range. They are used in automatic systems to control air pollution around industrial plants, in hospitals and factories, but also to prevent high levels of pesticides in agriculture products. (author)