The Bi-Disc Glassy Carbon Electrode for Determination of Vitamin K2 (Menaquinone) Using Stripping Voltammetry

Abstract

This paper presents a new type of the working electrode - bi-Disc Glassy Carbon Electrode (b-DGCE). An innovative design of the electrode surface consists of two glassy carbon discs (ϕ = 1.0 mm) symmetrically placed on the lateral surface of the guidewire formed with chemically resistant resin. The results obtained during characterization of the electrode, conducted by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), were consistent with the reversible reaction theory. The b-DGCE was constructed and used as a working electrode for determination of vitamin K2 (VK2) by the differential pulse adsorptive stripping voltammetry (DP AdSV). The electrochemical behavior of VK2 on the b-DGCE was investigated. Parameters affecting the stripping performance, such as composition and concentration of the supporting electrolyte as well as several key instrumental parameters were investigated and optimized. Under the optimized experimental conditions, a linear voltammetric response was received for VK2 in the concentration range from 0.06 to 0.55 mg·L−1 with limit of detection (LoD) of 0.017 for cathodic and 0.021 mg·L−1 for anodic scans, for a short accumulation time of 10 s. Repeatability of the method, expressed as RSD (n = 5) was 2.12 and 1.37 mg·L−1 for cathodic and anodic scans, respectively.