BDD electrodes modified with metal nano-catalysts for coffee discrimination in real samples

Abstract

An amperometric sensory approach based on boron-doped diamond (BDD) electrodes decorated with transition metals nano-catalysts was assessed for coffee discrimination in real samples. Thus, a bare BDD electrode along with four BDD electrodes modified respectively with Platinum/Iridium (PtIr), Platinum/Gold (PtAu), Gold/Ruthenium (AuRu) and Ruthenium (Ru) were investigated altogether in a broadly selective electrode array configuration to detect electro-active species in coffee samples. The transition metal nanoparticles were deposited onto BDD by sputtering thin metal layers onto polycrystalline BDD by a physical vapor deposition method, followed by a heat treatment at 700 °C under oxygen-free atmosphere. Such as process led to stable populations of strongly adherent nanosized metal particles over BDD surfaces as characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry. Chemometric analysis was adopted to examine the relevant parameters of the amperometric detection for classifying four coffee capsule samples. Promising results were obtained towards a new sensor technology to artificially predict taste for foodstuff analysis.