Chromatographic behaviour of aromatic compounds on anion-exchange resins in various carboxylate forms

Abstract

Phenols, benzyl alcohols and aromatic carboxylate ions were chromatographed on an anion-exchange resin in aqueous acetate, glycolate, butyrate and tartrate solutions. Non-polar interactions of alkyl groups and hydrogen bonding between phenolic hydroxyl protons and the resin led to increased distribution coefficients of both ions and non-electrolytes, while internal hydrogen bonding between phenolic and vicinal methoxyl groups suppressed the hydrogen bonding with the resin. The distribution coefficients of most aromatic carboxylate ions were higher in 0.5 M than in 0.3 M sodium tartrate solution. A large increase in the activity coefficients of the aromatic ions in the eluent with increasing tartrate concentration explains this abnormal effect, which parallels the high salting out of aromatic non-electrolytes in tartrate compared to the other eluents.