ANALYTE IDENTIFICATION IN ION CHROMATOGRAPHY - ELECTROMIGRATION GOVERNED CHRONOAMPEROMETRIC PROFILES

If a DC voltage is applied between two electrodes defining the boundaries of a small volume containing a stationary acid electrolyte, the resulting chronoamperogram is characteristic of the anion of the acid and can be used for identification purposes. Factors that affect the results obtained and their reproducibilities have been identified and studied using two 2-electrode cell designs. One parameter that affects the day-to-day reproducibility of the results and is relevant to the use of the technique as an adjunct to suppressed ion chromatography is the impurity level of the eluent. High purity electrodialytically generated eluents constitute one solution. To see if impurity problems could also be circumvented by an alternate experimental arrangement, a cell was devised in which the trapped eluite was subjected to electromigration using a third electrode and a high electric field. While the influence of the impurities on the chronoamperometric profile generated by the analyte ion of interest could not be eliminated under the conditions of the present experiments, it is suggested that this design may have significant utility for future experiments, including tandem ion chromatography-capillary electrophoresis.