SEPARATION OF WATER-SOLUBLE P-SULFONATED CALIXARENES 4-HYDROXYBENZENE, 6-HYDROXYBENZENE AND 8-HYDROXYBENZENE AND 4-HYDROXYBENZENE SULFONATE BY USE OF CAPILLARY ZONE ELECTROPHORESIS

A method for the separation of sulfonated calixarenes 4, 6 and 8 and the 4-hydroxybenzene sulfonate monomer by capillary zone electrophoresis with direct UV absorbance detection is described. The electroosmotic flow (EOF) decreases with addition of KC and reverses with addition of Mg2+. The suppression of the EOF upon the addition of K+ slightly improves the separation of the calixarenes and the monomer. However, the elution times of those compounds increase almost 35 min. The reversal of the EOF by addition of Mg2+ reduces the migration time and also improves the separation efficiency. The calixarenes are baseline separated in less than 14 min by use of a borate buffer with the addition of 4.0, 6.0 or 12.0 mM MgCl2 at pH 8.3.