Polymeric ionic liquid as a background electrolyte modifier enhancing the separation of inorganic anions by capillary electrophoresis

A novel and easy method for the separation of inorganic anions by capillary electrophoresis using a polymeric ionic liquid (PIL), poly(1-vinyl-3-butylimidazolium bromide) as a background electrolyte modifier has been developed. The PIL has been proved to generate a reversed electroosmotic flow which reduces the analysis time and improves the separation significantly. Effects of the PIL concentration and buffer composition (pH and concentration) were evaluated on basis of the resolution and efficiency of the sample. Under optimum conditions, good separation of six model inorganic anions was achieved with high efficiency and excellent reproducibility within 3 min. The results obtained indicate that the combination of reversed EOF and the association between the analytes and the PIL on the capillary wall or BGE play a prominent role in the separation of anions. Therefore, the PIL presents a useful alternative for the BGE modifier in the study of inorganic anions by CE.