Ion-exclusion chromatography of benzenecarboxylic acids on an unmodified silica-gel column

In order to demonstrate the effectiveness of two unmodified silica-gel (Develosil 30-5) columns (300x7.8 mm I.D.) used in series for the ion-exclusion chromatographic separation of mono-, di-, tri-and tetrabenzenecarboxylic acids, the elution behavior of benzenecarboxylic acids and phenol was investigated. When using water as an eluent, many benzenecarboxylic acids were co-eluted and the separation was not satisfactory. However, when using 5 mM sulfuric acid (pH 2.0) as the eluent, excellent separation and high detection sensitivities for many benzenecarboxylic acids and phenol were achieved in 40 min using UV detection at 200 nm. (C) 1997 Elsevier Science B.V.