Simple and Rapid Quantification of Folic Acid in Pharmaceutical Tablets using a Cathodically Pretreated Highly Boron-doped Polycrystalline Diamond Electrode

A simple, rapid, and sensitive electroanalytical method for the direct quantification of folic acid was developed using square-wave voltammetry with a cathodically pretreated highly boron-doped polycrystalline diamond electrode. The morphology and structure of this electrode were investigated by scanning electron microscopy and Raman spectroscopy. The electrochemical behavior of folic acid was studied by cyclic voltammetry and an irreversible oxidation peak was observed at +0.78 volt vs. Ag/AgCl in Britton-Robinson buffer at pH 5. Using optimized square-wave voltammetric parameter values, the response of folic acid was linear from 0.1 to 167 micromolar with a limit of detection of 30 nanomolar with good repeatability. The influence of some interfering compounds was also evaluated. The method was successfully applied to the quantification of folic acid in pharmaceutical tablets. Considering the importance of the analyte upon human health, the boron-doped diamond electrode may be employed as an effective alternative electroanalytical approach.