Determination of kojic acid based on the interface enhancement effects of carbon nanotube/alizarin red S modified electrode

Based on non-covalent interactions such as π–π stacking, van der Waals interactions and strong adsorption, alizarin red S (ARS) interacts with multi-walled carbon nanotubes (MWNT), improving the solubility of MWNT in water and resulting in a stable MWNT/ARS solution. By successive cyclic sweeps between 0.0 and 2.2 V in the MWNT/ARS solution, a MWNT/ARS composite film was fabricated on an electrode surface. The electrochemical behaviors of kojic acid at the bare electrode, the ARS film-modified electrode and the MWNT/ARS film-modified electrode were investigated. It was found that the oxidation signal of kojic acid significantly increased at the MWNT/ARS film-modified electrode, which was attributed to the unique properties of MWNT such as large surface area, strong adsorptive ability and subtle electronic character. The effects of pH and cyclic number of electropolymerization were examined. A rapid, sensitive and simple electrochemical method was then developed for the determination of kojic acid. This method exhibits good linearity over the range from 4.0 × 10−7 to 6.0 × 10−5 mol L−1, and the limit of detection is as low as 1.0 × 10−7 mol L−1. In order to validate feasibility, the MWNT/ARS film-modified electrode was used for quantitative analysis of kojic acid in food samples.