Application Of Capillary Electrophoresis Coupled With Carbon Fiber Electrode Detection

Carbon fiber, a filamentous carbon, is an ideal electrode material for the determination of electroactive compound due to its high electrical conductivity, anti-causticity and high strength. Coupling the capillary electrophoresis with carbon fiber amperometric detection has been proved to be a powerful separation technique with high resolution and low sample consumption and high sensitivity, which is in conformity with the development trend of modern science in terms of economy, cleaning and simplicity.Antioxidants, as food additives, have an extensive applied prospect in food industry. Two important antioxidants Propyl gallate(PG) and Butylated hydroxyanisole(BHA)display high chemical activity for suppressing chain initiation, or breaking chain propagation of the peroxidation of unsaturated fatty acids. Thus, the study on chemical properties and content of PG and BHA is very important. The aim of this study was to investigate the potential of the method for the determination of BHA and PG, and to establish suitable detection conditions based on their oxidation characteristic.A value of 0.70 V was selected as a suitable detection potential, where a high and stable electrochemical signal was obtained. An increase of the separation efficiency was observed by increasing the separation voltage from 12 to 20 kV. An improved separation resolution was achieved under basic conditions and a higher peak current of BHA was obtained at pH 8.84. Borax was added to the running buffer at pH 8.84 while aiming to improve the resolution of the antioxidants. The mutual action between three hydroxide radicals of the PG molecule and the boric ion prolonged the migration time of PG, while improving the resolution. There was good linearity of the analytes in the range of 1.8 - 180.2μg mL-1 for BHA and 10.6 - 212.2μg mL-1 for PG, respectively. The LODs for BHA and PG were 1.4μg mL-1 and 1.1μg mL-1, respectively. The linearity and LODs are adequate for the usual analytical requirements. The method as a complementary technique to the traditional methodologies is an original efficient approach for the determination of antioxidants in food.