Simultaneous Determination of Peroxide Hydrogen and Ascorbic Acid by Capillary Electrophoresis with Platinum Nanoparticles Modified Micro‐disk Electrode

Abstract

Abstract In this study, the first application of a capillary zone electrophoresis‐electrochemical detection (CE‐ECD) method for concurrent determination of hydrogen peroxide (H 2 O 2 ) and ascorbic acid (AA), was developed using the Pt nanoparticles (PtNPs) modified Pt micro‐disk electrode (PtME). The electrocatalytic activity of the modified electrode for H 2 O 2 and AA was characterized by cyclic voltammetry. Under optimized experimental conditions, highly linear calibration plots were observed for both H 2 O 2 and AA, with concentration linear ranges of 0.8 μM to 0.8 mM and 1.0 μM to 0.8 mM. Detection limits of 0.2 μM H 2 O 2 and 0.5 μM AA were determined on the basis of the signal‐to‐noise characteristics (S/N=3) of an electropherogram. Compared with the unmodified PtME, the sensitivity was promoted in that PtNPs/PtME provided an increased effective electrode surface and high catalytic activity toward H 2 O 2 and AA. Using this method, the added H 2 O 2 and AA in Mizone, a kind of functional drink, were detected, and the concentration of AA was found to be 2.33 mM ( n =3). The recovery rates were 95.3 % for H 2 O 2 and 98.7 % for AA. The novel approach provided a wide linear range, low detection limit, good reproducibility and stability. It will provide a new insight into the balance of reactive oxygen species and antioxidant in biological systems.