Electroanalysis of Gallic and Ellagic Acids at a Boron-doped Diamond Electrode Coupled with High-performance Liquid Chromatography

Electrochemistry of gallic acid (GA) and ellagic acid (EA) was investigated by cyclic voltammetry (CV) using a bare boron-doped diamond (BDD) electrode. CVs indicate that the electro-oxidation of both GA and EA are quasi-reversible processes. High-performance liquid chromatography (HPLC) coupled with a BDD electrode poised at+1.4 V offers the limit of detection (LOD, S/N=3) of 60 and 200 nM for GA and EA, respectively. The optimized method was then applied to the detection of both acids in Islay, Highland and Scotch whiskeys, with the highest concentrations found in a 14-year-old Highland whiskey.