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.

中文翻译：

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还原氧化石墨烯/金纳米粒子修饰的丝网印刷电极测定棕榈酸

棕榈油是当今世界上生产的主要油脂之一。棕榈油的质量对于研究至关重要，质量指标之一是游离脂肪酸（FFA）的含量。因此，在这项研究中，已经探索了一种电化学法测定FFA，以替代传统方法（滴定法）。电化学方法是基于电化学还原氧化石墨烯（rGO）与通过滴铸技术沉积到丝网印刷碳电极（SPCE）上的金纳米颗粒（AuNPs）结合而开发的。在含有高氯酸锂（LiClO _4）的乙腈/水混合物中，研究了2-甲基-1,4-萘醌（VK ₃）在棕榈酸存在下在修饰电极上的伏安行为。）。棕榈酸的电化学检测是基于VK ₃的伏安还原，以形成与棕榈酸浓度成比例的相应氢醌。在最佳条件下，所开发的方法在0.192 mM至0.833 mM的浓度范围内与棕榈酸表现出良好的线性关系，检出限为0.015 mM。对开发的系统的探索有望实现对棕榈油中FFA含量测定的高灵敏度和出色的选择性。