Capillary electrophoretic separation of anions in dimethylformamide–acetic acid medium

Abstract

A low viscosity, low conductivity medium derived from N,N-dimethylformamide and acetic acid was synthesized and studied for the feasibility as a background electrolyte for capillary electrophoresis-capacitively coupled contactless conductivity detection of anions. The background electrolyte could separate anions prepared in solvents of different dielectric constants, polarities, and viscosities, i.e., methanol, acetonitrile, sulfolane and water, with detection limits of 0.83–3.83 × 10⁻⁶ mol L⁻¹ for BF₄⁻, ClO₄⁻, PF₆⁻, I⁻, NO₃⁻, Br⁻ and Cl⁻. Finally, the method was applied to determining inorganic anions in tap water and honey samples as well as identifying alkyl sulfate surfactants in a shampoo sample.