Cheap pencil graphite electrodes for rapid voltammetric determination of chlorogenic acid in dietary supplements

Abstract

A disposable, cheap and easily available pencil graphite electrode (PGE) was used to develop, for the first time, a rapid voltammetric method for chlorogenic acid (CGA) determination. Cyclic voltammograms emphasised a quasi-reversible, diffusion controlled and pH dependent electrode process. Differential pulse voltammetry (DPV) applied to the anodic peak was used for the quantitative determination of CGA. The linear range, the limit of detection and the limit of quantification were 1 × 10⁻⁷ to 5 × 10⁻⁴ mol L⁻¹ CGA, 7.14 × 10⁻⁸ mol L⁻¹ CGA and 2.1 × 10⁻⁷ mol L⁻¹ CGA, respectively, being similar to or even better than those reported in the literature. The developed DPV on PGE method was applied with good results to the quantitative determination of CGA in commercially available green coffee extract based dietary supplements. The results compared well with those obtained by the Folin–Ciocalteu method, a fact proved by the statistical analysis.