A SIMPLE METHOD FOR THE DETERMINATION OF GALLIC ACID IN THAI HERBS BY CYCLIC VOLTAMMETRY

Abstract

The present work aims to determine the amount of gallic acid in the herbs using cyclic voltammetry.  For electrochemical analysis, the system consists of three electrodes, including a glassy carbon electrode as the working electrode, an Ag/AgCl electrode as reference electrode, a stainless steel as the counter electrode. The quantitative determination of gallic acid was carried out in phosphate buffer solution.  Electrochemical behavior of gallic acid has been studied, the anodic peak current of gallic acid was observed at the potential of 0.45 and 0.70 V, at scan rate of 0.1 V/s. Cyclic voltammograms of gallic acid showed the linear response in the range of 0.10 to 1.07 mM. Moreover, the proposed method was successfully applied to analyze gallic acid in Pandanus amaryllifolius Roxb., Camellia sinensis var. sinensis and Ocimum basilicum Linn and the percentage recovery was in the range 80.22 - 96.38%.