Capillary electrophoresis with capacitively coupled contactless conductivity detection for the determination of propionate and sorbate in bread.

We propose a simple and fast method for the determination of the preservatives propionate and sorbate in bread using capillary electrophoresis with capacitively coupled contactless conductivity detection. The preservatives were quickly extracted from bread using ultra-pure water and ultrasonic energy. The separation of the analytes, with good resolution, was achieved in about 7 min. The proposed method showed good linearity with coefficients of determination > 0.99 for both the preservatives. The limits of quantification of the method were 0.11 and 0.21 g/kg for propionate and sorbate, respectively. The accuracy of the method was evaluated by recovery tests, and the obtained recoveries varied from 88 to 94% for sorbate and 86 to 102% for propionate. The proposed method was successfully applied for the determination of propionate and sorbate in commercial samples of sliced white bread.