Effects of contamination on ion mobility detection after gas chromatography.

The ion mobility detector is a device that can be used for the selective, ultratrace detection of organic compounds after capillary gas chromatography. It is the only gas chromatographic detector which does not require heteroatomic compounds for selective response, yet concern is often expressed over its quantitative capabilities. Being a secondary ionization device, competitive charge transfer reactions from unseparated compounds or detector gas contamination may decrease the accuracy of measurement. This paper investigates the effects of both electronegative and electro-positive contaminants on the detector's response. In general, it was found that contamination of the detector did affect response but no more severely than in conventional detectors such as the electron-capture detector or the flame ionization detector.