EFFECT OF ELECTROLYTE COMPOSITION IN THE CAPILLARY ELECTROPHORETIC SEPARATION OF INORGANIC ORGANIC ANIONS IN THE PRESENCE OF CATIONIC POLYMERS

摘要

Electrolyte modification with two cationic polyelectrolytes has been investigated for the separation of inorganic anions, aliphatic and aromatic carboxylic acids, and sulphonic acids. Changes in migration rates and separation selectivity, arising from hydrophobic interactions, ion exchange, and changes in electroosmotic flow were studied for benzoate, chromate and phosphate + chloride counter-ions as a function of pH, and for the addition of methanol and acetonitrile. Large changes in separation selectivity, for aliphatic and sulphonic acids, were observed with benzoate electrolytes as compared to chromate electrolytes. In addition, electroosmotic how was faster in the former separation electrolytes by about 65%. Changes in selectivity as a result of hydrophobic interactions were investigated with a series of aromatic acids where shifts in migration order were observed as function of polyelectrolyte concentration. For inorganic anions, in chromate electrolytes at a constant concentration of polyelectrolyte, the addition of methanol or acetonitrile decreased migration rates by as much as 67%. The analytical merits of the methodology were examined for a potash (concentrated KCl) sample and a simulated decontamination solution containing EDTA, Fe3+(EDTA) and oxalate. [References: 54]