Analytical Sciences

Capillary Electrophoresis-Amperometric Determination of Antioxidant Propyl Gallate and Butylated Hydroxyanisole in Foods

Qian XIANG,*^,**^,*** Ying GAO,**^,*** Yuanhong XU,** and Erkang WANG**

*Key Laboratory Automobile Materials of Ministry of Education, College of Materials Science and Engineering, Jilin University, Changchun 130021, China
**State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130021, China
***Department of Applied Chemistry, Changchun Institute of Technology, Changchun 130021, China

Capillary electrophoretic separation coupled with end-column amperometric detection for the simultaneous quantification of butylated hydroxyanisole (BHA) and propyl gallate (PG) in food was developed. Important factors affecting separation and detection, such as the running buffer, separation voltage, and detection potential, were investigated in detail. An improved working electrode preparation method was used, where a carbon disk of 33 µm in diameter was sealed in a tip and positioned opposite the outlet of a capillary. The experiments indicated that the preparation method was simple, and the obtained electrode exhibited good flexibility and stability for the determination of phenolic antioxidants. The separation was carried out within 5 min using a 50 cm length capillary, with a solution containing 5 mM phosphate and 5 mM borax of pH 8.84 as a separation buffer, and a separation potential of 20 kV. Amperometric detection was achieved with an applied potential of 0.70 V versus Ag|AgCl| saturated KCl. There was excellent linearity between the peak current and the concentrations of the analytes in the range of 1.8 - 180.2 µg/mL for BHA and 10.6 - 212.2 µg/mL for PG, respectively. Relative standard deviations of 4.92% for BHA and 5.27% for PG were obtained, respectively. The developed method was successfully applied for the determination of antioxidants in several commercial foods.

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