Reduced Graphene Oxide/Gold Nanoparticles Modified Screen-Printed Electrode for the Determination of Palmitic Acid

Abstract

Palm oil is one of the major oils and fats produced in the world today. The quality of palm oil is crucial to be investigated, and one of the quality indices is free fatty acid (FFA) content. Therefore, in this study, an electrochemical approach for the determination of FFA has been explored as an alternative to replace the conventional method (titration method). The electrochemical method was developed based on electrochemically reduced graphene oxide (rGO) coupled with gold nanoparticles (AuNPs) deposited onto a screen-printed carbon electrode (SPCE) via drop-casting technique. The voltammetric behaviour of 2-methyl-1,4-naphthoquinone (VK3) in the presence of palmitic acid at the modified electrode was investigated in an acetonitrile/water mixture containing lithium perchlorate (LiClO4). The electrochemical detection of palmitic acid was based on the voltammetric reduction of VK3 to form the corresponding hydroquinone which is proportional to the concentration of palmitic acid. Under optimum conditions, the developed method showed a good linear relationship towards palmitic acid in the concentration ranging from 0.192 mM to 0.833 mM with the detection limit of 0.015 mM. The exploration of the developed system is expected to achieve high sensitivity and excellent selectivity towards the determination of FFA content in palm oil.