ION MOBILITY SENSOR IN ENVIRONMENTAL ANALYTICAL-CHEMISTRY - CONCEPT AND 1ST RESULTS

Ion mobility spectrometry is a technique for generating ions at atmosp heric pressure via ion-molecule reactions, and for analysing them in a n ion drift tube. The time required for the ions to traverse the lengt h of the drift tube is mainly a function of the mass and the charge of the ions. Besides, ion shape and polarizability also affect the drift time. Ion mobility spectrometry does not allow structural identificat ion and quantification of unknown substances in mixtures. However, und er certain boundary conditions it provides selective fingerprints of t he substances to be observed, and operates at the ppbv concentration l evel and the millisecond time scale. Through further miniaturization o f a recently developed instrument of this type an ion mobility sensor is to be constructed. This sensor includes drift channel, operating sh utter, collecting electrode, electronic data acquisition and translati on board. The sensor makes possible to obtain real-time ion mobility s pectra. We present and discuss the concept of a small ion mobility spe ctrometer, its operation principle and first results on the way toward s its further miniaturization.