ELECTROSTATIC ION CHROMATOGRAPHY

Ion chromatography using ''strong/strong'' charged zwitterionic micellar-coated stationary phase with pure water as the mobile phase has been investigated for the separation of inorganic solutes and organic zwitterionic solutes. Retention mechanisms of the zwitterionic charged stationary phase in ion chromatography have also been investigated using a conductivity detector. For inorganic analytes, anions and their countercations are always eluted together. The retention times of inorganic solutes are only dependent on the anions. According to experimental results, we suggest that analyte anions and their countercations combine to make'' ion-pairing-like'' forms and are separated by the simultaneous electrostatic attraction and repulsion interactions between the zwitterionic charged stationary phase, analyte anion, and its countercation. 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 zwitterionic 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.