ELECTROSTATIC ION CHROMATOGRAPHY

Ion chromatography using ''strong/strong'' charged zwitterionic micell ar-coated stationary phase with pure water as the mobile phase has bee n investigated for the separation of inorganic solutes and organic zwi tterionic solutes. Retention mechanisms of the zwitterionic charged st ationary phase in ion chromatography have also been investigated using a conductivity detector. For inorganic analytes, anions and their cou ntercations are always eluted together. The retention times of inorgan ic solutes are only dependent on the anions. According to experimental results, we suggest that analyte anions and their countercations comb ine to make'' ion-pairing-like'' forms and are separated by the simult aneous electrostatic attraction and repulsion interactions between the zwitterionic charged stationary phase, analyte anion, and its counter cation. The formation of the simultaneous electrostatic attraction and repulsion interactions between the same and opposite charges can also be used to explain the retention behavior involved in the separation of organic zwitterionic solutes by the strong/strong charged zwitterio nic stationary phase with pure water as the mobile phase. The present system was used for the rapid determination of iodide and thiocyanate in human saliva samples.