Long-chain alkylimidazolium ionic liquids, a new class of cationic surfactants coated on ODS columns for anion-exchange chromatography

Separations of common inorganic anions were carried out on ODS columns coated with two long-chain alkylimidazolium ionic liquids ([C₁₂MIm]Br and [C₁₄MIm]Br) as new cationic surfactants for ion chromatography. With phthalate buffer solution as the mobile phases and non-suppressed conductivity detection, high column efficiencies and excellent selectivity were obtained in the separation of inorganic anions. Chromatographic parameters are calculated and the results show that the coated column possesses significant potential for the analysis of some inorganic anions such as CH₃COO^-, IO₃^-, Cl^-, BrO₃^-, NO₂^-, Br^-, NO₃^-, SO₄^2- I^-, BF₄^-, and SCN^-. The effect of eluent PH values on the separation of anions has been studied on the column coated with [C₁₂MIm Br. The stability of the coated columns was also examined.