High electric field strengths in micellar electrokinetic capillary electrophoresis with ionic liquids as modifiers

In this study, a method for the separation and determination of basic analytes in aqueous capillary electrophoresis (CE) was developed based on high electric field strengths and ionic liquids (ILs). The resulting electric field strengths ranged from 500 to 1000 V/cm. Trishydroxymethylaminomethane (Tris) and sodium cholate (SC) were used as main electrolytes. The ionic liquids 1-ethyl-3-methylimidazoium tetrafluoroborate (1E-3MI-TFB) and 1-butyl-3-methylimidazoium tetrafluoroborate (1B-3MI-TFB) were used as modifiers to improve the separation efficiency and selectivity. It was shown that increasing the applied electric field strengths not only caused short analysis time, but also did not induce excessive Joule heating in the capillary when ionic liquids were used as modifiers. The susceptibility to high electric field of separation efficiency in capillary electrophoresis, with the effect of ionic liquids, was subsequently discussed, and the developed method was used to analyze three model analytes in Sinacalia tangutica. The accurate results illustrated that high electric field strength with the ionic liquids was feasible in CE.