SIMULTANEOUS SEPARATION OF INORGANIC CATIONS AND ANIONS BY ION CHROMATOGRAPHY USING STRONG ANIONIC ZWITTERIONIC MIXED MICELLES AS THE STATIONARY-PHASE/

Mixed micelles obtained by mixing SDS (sodium dodecylsulfate) with Zwi ttergent-3-14 (N-tetradecyl-N, N-dimethyl- 3-ammonio 1-propanesulfonat e) are used as a dynamic stationary phase for the simultaneous ion chr omatography of inorganic cations and anions. Analyte cations are separ ated by the negative charges in the SDS based upon ion-exchange intera ctions while analyte anions are separated by both the positive and neg ative charges in Zwittergent-3-14 based upon simultaneous electrostati c attraction/repulsion interactions. The ratio of SDS/Zwittergent-3-14 , which constitutes the stationary phase is an important factor in the determination of the retention times and elution orders of the analyt e ions. The investigation of the mechanisms involved and the practical applications are discussed in this paper.