With the electrolytic conducyivity detector, compounds containing halogens. Sulfur, or nitrogen are mixed with a reaction gas in a small reactor tube.The producrs are then dissolved in a liquid that produces a conductive solution. The change in con ductivity as a result of the presence of the active compound is then measured.In the photoionization detector, molecules are photoionized by UV radiation.The ions and electrons produced are then collected with a pair of biased electrodes,and the resulr-ing current is measured.The detector is often used for aromatic and other molecules that are easily photoionized.