Ion Exclusion Chromatography of Aromatic Acids

The determination of aromatic acids by ion exclusion chromatog-raphy is challenging due to peak tailing and the long retention time of hydrophobic solutes. This review discusses the retention mechanisms and the factors affecting retention, eluents and detec-tion methods used in ion exclusion chromatography of aromatic acids such as mono-, di-, tri- and tetra-carboxylic acids, amino acids, sulfonates and phenol. In addition, the different approaches used to improve the chromatographic separation of these com-pounds are also discussed. These approaches include introducing an internal gradient of the ionic strength, using vacancy ion exclu-sion chromatography, employing a hydrophilic cation exchange resin or adding a modifier such as heptanol to the dilute sulfuric acid mobile phase. The applications of these methods in the ana-lysis of aromatic acids are provided with a table summarizing the stationary phases, the mobile phases and the detection methods