A type of gas detector used in gas chromatography. Individual components of a gas mixture elute from the column and are burned in a hydrogen flame, where a large quantity of ions are produced. These ions are vented through a collector tube, which is maintained at some electrical potential so that a current passes through the ions produced in the flame to the collector. The current measured is proportional to the quantity of eluted compound. The technique has found the most use for the measurement of organic compounds, particularly hydrocarbons, in the atmosphere.