CHROMATOGRAPHIC SIMULATION OF THE EFFECT OF A POLYVALENT COUNTER ION ON RETENTION BEHAVIOR AND PEAK INTENSITY OF SULFATE

The effect of a mobile phase polyvalent counter ion on the retention behavior and peak intensity of sulfate in nonsuppressed ion chromatography was quantitatively studied using a chromatogram simulation method. In this study, both indirect photometric detection (IPD) method and conductometric detection (CD) method were evaluated. With the IPD method, the retention of sulfate was observed to decrease in the presence of the polyvalent counter ion (Trien) without any change in peak intensity. With the CD method, however, peak intensity of sulfate decreased and, under some conditions, gave a negative peak in simulation as was also observed in actual experiments. The present work demonstrates the possibility of predicting the effect of a polyvalent counter ion on sulfate retention without resorting to physical experiments.