Journal of Chromatography, 516 (1990) 263-270 Elsevier Science Publishers B.V., Amsterdam CHROM. 22 58 1 Retention of eleven priority phenols using micellar electrokinetic chromatography C. P. ONG, C. L. NG, N. C. CHONG, H. K. LEE and S. F. Y. LI* Department of Chemistry, National University of Singapore, Kent Ridge, Singapore W I1 (Singapore) ABSTRACT The use of micellar electrokinetic chromatography (MECC) for the separation of eleven substituted phenols listed by the United States Environmental Protection Agency as priority pollutants was investigated. Solutions of potassium and sodium dodecyl sulphate in phosphate-borate buffer of pH 6.6, 7.0 and 7.5 were used as the electrophoretic media. Satisfactory separation of the eleven phenols was obtained using a lSO+m capillary at 10 kV and pH 6.6 with a solution containing both sodium and potassium dodecyl sulphate. Observations on the retention behaviour of the phenols in MECC were related to their physico-chemical properties. INTRODUCTION Capillary zone electrophoresis (CZE) and micellar electrokinetic chromatogra- phy (MECC) have become popular separation techniques owing to their inherently high separation efficiency I4 The analysis of a series of chlorophenols using MECC . has been reported5. However, the application of these techniques to the analysis of environmental pollutants has rarely been investigated. Substituted phenols are of great environmental concern owing to their high toxicity. The United States Environmental Protection Agency (USEPA) lists the elev- en phenols shown in Fig. 1 as priority pollutants6. Some of these phenols, which originate from such diverse sources as pesticide application, industrial wastes, water supplies and automobile exhausts, are highly toxic even at low concentrations. A widely used technique for the analysis of phenols is high-performance liquid chroma- tography (HPLC) with either reversed-phase isocratic or gradient elution’-lo. How- ever, owing to the inherent limited resolving power of conventional HPLC tech- niques, optimization of the separation of the phenols often involves complicated procedures or a large number of experiments l1 In this work, the use of MECC for . the separation of the eleven priority phenols was investigated. For this purpose, two types of micellar solutions were used to examine the selectivity. The retention beha- viour of these compounds in MECC at various pH values is discussed. 0021-9673/90/$03.50 0 1990 Elsevier Science Publishers B.V.