Electrolytic conductivity detector halogen-compounds

The halogen selective microcoulometric and electrolytic conductivity detectors have been applied extensively to the analysis of halogenated compounds in drinking water. Both have adequate sensitivity for the application and sufficient selectivity to allow reasonably accurate identifications with the retention time data. However, these detectors are also best applied to well defined samples where the probability of unexpected compounds is low. 

The halogenated method employs a packed column of 1% SP-1000 on Carbopak-B (60-80 mesh) as its primary analytical column. The column is 8-ft X 0.1-in. i.d. It is operated at a helium flow rate of 40 mL/min under programmed temperature conditions of 45 °C isothermal for 3 min, then 8 °C/min to 220 °C, and then held at 220 °C for 15 min or until all compounds have eluted. An electrolytic conductivity detector operated in the halide-specific mode is used for measurement. 

The FPD does not respond to nitrogen or halogens the AFD does, but much less so than to phosphorus. In those areas, the competition comes primarily from other types of detectors. These are the micro-coulometric and the electrolytic conductivity detectors in the nitrogen and halogen areas and, of course, the electron capture detector for chlorinated hydrocarbons and other electron-attaching compounds. 

With the electrolytic conductivity detector, compounds containing halogens, sulfur, or nitrogen are mixed with a reaction gas in a small reactor tube. The products are next dissolved in a liquid, which produces a conductive solution. The change in conductivity as a result of the presence of the active compound is then measured. In the photoionization detector, molecules are photoionized by ultraviolet radiation. The ions and electrons produced are then collected with a pair of biased electrodes, and the resulting current is measured. The detector is often used for aromatic and other molecules that are easily photoionized. 

Selective GC detectors aid in the detection and identification of compounds containing specific elements halogens with electron capture detector (BCD) or electrolytic conductivity detector (ELCD) nitrogen and phosjAorus with nitrogen-phosphorus detector (NPD) sulfur and phosphorus with flame photometric detector (FPD) and sulfur with sulfur chemiluminescence detector (SCD). The development of the atomic... 

Two of the more recently developed detectors, namely, the Hall electrolytic conductivity detector (ELCD) and the photoionization detector (PID) are recommended by the EPA for the analysis of volatile and semivolatile halogenated organic compounds and low molar mass aromatics. Chemical emission based detectors, such as the thermal energy analyzer (TEA) for its determination of... 

Determination of Aromatic and Halogenated Volatile Organic Compounds Using Photoionization and Electrolytic Conductivity Detectors... 

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