Para-hydroxybenzoic acid as an indirect detection buffer in capillary zoneelectrophoresis

Para-hydroxybenzoic acid (p-HBA) has been used as indirect UV detection buf fer in capillary zone electrophoresis (CZE). Being an UV-absorbing dibasic acid, pHBA provides both the necessary buffering for pH control over a wide range and UV absorbance for indirect detection. With sodium dodecyl sulfat e (SDS) as a probe, a CZE method using p-HBA solution as running buffer was developed to analyze anions, especially ones with low electrophoretic mobi lities. The method was used to separate homologous series of sulfonates, SD S in a formulation sample, and SDS in a standard.