Determination of inorganic anions in human saliva by zwitterionic micellar capillary electrophoresis

Capillary electrophoresis (CE) using sulfobetaine-type zwitterionic micelles as the background electrolyte (BGE) has been used to determine inorganic anions in human saliva. The zwitterionic micelles resulted in unique migration behavior for the separation of inorganic anions. They also prevented adsorption of proteins on the inner wall of the capillary. These properties of the zwitterionic micelles enabled the direct determination of inorganic anions in human saliva. Three species of inorganic anions, NO₂^-, NO₃^-, and SCN^-, were found in real samples and the analysis was achieved within 3 min. Direct UV-absorption was used as the detection method and the detection limits for these anions were 2.0, 1.0, and 5.0 μmol L^-1, respectively (0.09, 0.06, and 0.30 μg mL^-1).