A New Approach in the Electrochemical Determination of Folic Acid in Foods: Use of a Polished Silver Solid Amalgam Electrode

This work describes the use of polished silver solid amalgam electrode (p-AgSAE) and square wave voltammetry in the voltammetric determination of folic acid (FA). Experimental and voltammetric parameters were previously optimized. A well-defined voltammetric peak indicated a reversible redox reaction involving reactant and product adsorption on the p-AgSAE surface. A linear relationship between peak current and FA concentration was obtained from 4 × 10 –7 to 1.1 × 10 –5 M with a correlation coefficient of 0.9981, inter-day and intra-day precision of 2.1 and 5.3%, respectively, detection limit of 1.1 × 10 –7 M, and quantification limit of 4 × 10 –7 M. This procedure was applied to FA determination in spinach and corn chip samples using a simple extraction, resulting in good percent recovery that confirmed suitable robustness of the proposed methodology and the use of p-AgSAE as an excellent alternative for FA determination without the use of modified electrodes or toxic waste generation from the mercury electrodes utilization.