Simple and fast method for simultaneous determination of propionate and sorbate in bread by capillary electrophoresis with UV spectrophotometric detection

A novel method for simultaneous determination of the preservatives propionate and sorbate in bread samples using capillary electrophoresis with diode array spectrophotometric detection is proposed. This method requires a simple and fast sample preparation using aqueous extraction with sonication aid. A background electrolyte (BGE) composed of 10 mmol L−1 benzoic acid, 15 mmol L−1l-histidine and 0.2 mmol L−1 of cetyltrimethylammonium bromide (CTAB) allowed the separation of the preservatives with good resolution in less than 5 min. Propionate was indirectly detected at 235 nm, and the sorbate was directly detected at 250 nm. The limits of quantification (LOQ) were 4.3 and 1.5 mg kg−1 for propionate and sorbate, respectively. The proposed method was successfully applied for analysis of commercial samples of sliced white bread.