ION MOBILITY SPECTROMETRY AFTER CHROMATOGRAPHY - ACCOMPLISHMENTS, GOALS, CHALLENGES

The authors designed and constructed an ion mobility spectrometer that was specifically suited for the detection of trace organics after separation by high resolution gas chromatography. Using a unique unidirectional flow design, problems associated with long residence times in the spectrometer were eliminated. The high resolution gas chromatograph insured the purity of standards and enabled the introduction of sufficiently small quantities of compounds. Microprocessor-controlled operation of the ion gates in the drift tube permitted both selective and nonselective detection of chromatographic effluent and the Fourier transform method of operation enabled spectra from rapidly eluting capillary chromatographic peaks to be captured 'on the fly'. It was also found that the linear range of the detector could be extended by the use of a photoionization source. Current goals and future challenges are discussed.