Vanillin (VN) is a flavouring substance commonly used in the food and pharmaceutical industry. The rampant use of VN has significant implications on human health. In this work, a sensitive and selective voltammetric sensor to detect VN in food essences and natural vanilla beans was elucidated using a poly(methyl orange) modified graphene paste electrode (PMOMGPE). The surface morphology of PMOMGPE and a bare graphene paste electrode (BGPE) was compared using field emission - scanning electron microscopy (FE-SEM) and electron transfer kinetics were analysed by Electrochemical impedance spectroscopy (EIS). The electrochemical activities of PMOMGPE and BGPE were assessed using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in 0.2 M phosphate buffer solution (PBS) of an optimum pH of 6.5 with an accumulation time of 20 s in a potential window of 0.2 V–1 V. Superior electrocatalytic activity was observed by PMOMGPE for the oxidation of VN, which is attributed to the high surface area and interactions between the polymer film and analyte. The VN sensor exhibited a low detection limit of 7.35 × 10⁻⁸ M by the DPV method and 20.19 × 10⁻⁸ M by the CV method. Various parameters like heterogeneous rate constant (k^o = 1.7 × 10⁻⁵ cm s⁻¹), number of electrons transferred (n = 2), and surface concentration (Γ = 0.8 nmol cm⁻²) were calculated. The selectivity of the prepared sensor for VN detection in the presence of common interferents such as metal ions and organic species was noteworthy. PMOMGPE was reliably used for the simultaneous analysis of VN along with indigo carmine (IC) and tartrazine (TZ). This facile VN sensor can be effectively used for real sample analysis, due to its simplicity and stability.

香兰素 (VN) 是一种常用于食品和制药行业的调味物质。VN 的猖獗使用对人类健康具有重大影响。在这项工作中，使用聚（甲基橙）改性石墨烯糊电极（PMOMGPE）阐明了一种灵敏且选择性的伏安传感器，用于检测食品香精和天然香草豆中的 VN。使用场发射-扫描电子显微镜 (FE-SEM) 比较 PMOMGPE 和裸石墨烯糊电极 (BGPE) 的表面形态，并通过电化学阻抗谱 (EIS) 分析电子转移动力学。使用循环伏安法 (CV) 和差分脉冲伏安法 (DPV) 在最佳 pH 值为 6 的 0.2 M 磷酸盐缓冲溶液 (PBS) 中评估 PMOMGPE 和 BGPE 的电化学活性。5 在 0.2 V-1 V 的电位窗口中积累时间为 20 秒。PMOMGPE 观察到了对 VN 氧化的优异电催化活性，这归因于高表面积和聚合物膜与分析物之间的相互作用。VN 传感器的检测下限为 7.35 × 10^-8  M 通过 DPV 方法和 20.19 × 10 ^-8  M 通过 CV 方法。计算了各种参数，如异质速率常数（k ^o  = 1.7 × 10 ^-5  cm s ^-1）、转移的电子数（n = 2）和表面浓度（Γ = 0.8 nmol cm ^-2）。在存在常见干扰物（如金属离子和有机物质）的情况下，所制备的 VN 检测传感器的选择性值得注意。PMOMGPE 可靠地用于同时分析 VN 以及靛蓝胭脂红 (IC) 和柠檬黄 (TZ)。由于其简单性和稳定性，这种简便的 VN 传感器可有效地用于实际样品分析。