Abstract: In order to establish a rapid detection technique of ascorbic acid (AA), with AA as template molecule and o-phenylenediamine (o-PD) as functional monomer, poly (o-phenylenediamine) (PPD) film was electropolymerized on the surface of a glassy carbon electrode using cyclic voltammetry (CV). Furthermore, the ultrapure water was used to elute the template molecules. The experimental conditions for the electropolymerization reaction were optimized and listed as follows:reaction medium: 0.20 mol/L HAc-NaAc buffer (pH 5.2), molar ratio of o-PD to AA: 1:2, potential range: 0-0.8 V, scan rate: 50 mV s-1. The electrochemical properties of the molecularly imprinted sensor were investigated using CV, square wave voltammetry (SWV) and current-time curve (I-t) methods. The response current of the sensor had good linear relationships with concentration of AA in the ranges of 1.0 x 10-6 - 1.0 x 10-3 mol/L and 1.0 x 10-3 - 4.5 x 10-3 mol/L, respectively. The detection limit was 4.9 x 10-7 mol/L. The proposed method was applied in the determination of AA in commercial orange juice, and 2,6-dichlorophenol indophenol titration method was used for verification. The results showed that the method was rapid, accurate and inexpensive, and was suitable for the determination of AA in orange juice and other food samples.
Template and target information: ascorbic acid, vitamin C
Author keywords: molecularly imprinted, ascorbic acid (AA), electropolymerization, Electrochemical sensor, Poly(o-phenylenediamine)