Analysis of inorganic anions by electrostatic ion chromatography using zwitterionic/cationic mixed micelles as the stationary phase

• Published in: Fresenius' journal of analytical chemistry Vol. 367; no. 7; pp. 641 - 644
• Main Authors: WENZHI HU, HADDAD, P. R, HASEBE, K, COOK, H. A, FRITZ, J. S
• Format: Journal Article
• Language: English
• Published: Berlin Springer 01.08.2000
• Subjects: Analytical chemistry; Chemistry; Chromatographic methods and physical methods associated with chromatography; Exact sciences and technology; Other chromatographic methods; Water; Ion chromatography; Inorganic anion; Amphoteric surfactant; Detection limit; Cationic surfactant; Mixed micelle; Selectivity
• ISSN: 0937-0633; 1432-1130
• DOI: 10.1007/s002160000436

The inability to separate fluoride, phosphate and sulfate by electrostatic ion chromatography (EIC) was overcome by using an ODS silica column coated with mixed zwitterionic-cationic surfactants as the stationary phase. The best results were obtained using the zwitterionic surfactant, 3-(N,N-dimethylmyristylammonium)-propanesulfonate (C19H41NO3S), and the cationic surfactant, myristyltrimethylammonium, CH3(CH2)13N+(CH3)3, in a 10:1 molar ratio in the column coating solution. With a dilute solution of sodium tetraborate as the eluent the model analyte anions were completely separated in the following elution order: F, HPO42-, SO42-, Cl-, NO2-, Br-, NO3-. The very early elution of phosphate and sulfate is most unusual and is unique to this system. Detection limits better than 1.1 x 10(-4) mM and linear calibration plots up to 7.0 mM were obtained with a suppressed conductivity system.