REVERSED-PHASE LIQUID-CHROMATOGRAPHY OF SOME POSITIONAL ISOMERS ON CALIX[6]ARENE-P-SULFONATE-BONDED SILICA

A silica-bonded, calix[6]arene-p-sulfonate (CAPS) stationary phase has been used in the reversed-phase separation of mono-substituted phenol (cresol, methoxyphenol, nitrophenol, aminophenol and chlorophenol) re gioisomers and some other aromatic positional isomers. Phenol isomers with polar and hydrogen-bonding groups (nitrophenol, aminophenol and m ethoxyphenol) are well resolved while isomers with nonpolar groups are not well resolved by highly aqueous, methanol mobile phases. Other ar omatic positional isomers investigated are also well separated on CAPS in aqueous or highly aqueous, organic mobile phases with optimum rete ntion.