In this report, phosphorus-doped graphitic carbon nitride (PgCN), a metal-free catalyst, was prepared via a one-step thermal polymerization technique. Additionally, PgCN-x with a different weight ratio of phosphorous doping (x = 1, 2, and 3 wt %) was successfully synthesized and their structural and morphological properties were evaluated. The developed modified electrodes were engaged for the determination of quercetin (QCN) using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. CV and DPV studies authenticate characteristic peaks ca. at +0.20 and +0.93 V (vs. GCE), respectively. Notably, the improved catalytic activity was perceived for PgCN-3 catalyst, which is 2-fold higher than pristine gCN, was possibly due to high phosphorous content. The quantitative analysis under optimized conditions revealed a comprehensive detection of QCN in the concentration range from 0.025 to 212.2 µM with the lowest detection limit of 1 nM. Interestingly, impedance spectroscopy results disclose a piece of additional evident information to uncover the P-doping by comparing with pristine gCN in the presence of negatively charged redox couple. The currently developed electrochemical method was successfully employed to determine QCN in commercially available fruit juice samples with an acceptable recovery ∼95%.

在本报告中，磷掺杂的石墨氮化碳 (PgCN) 是一种无金属催化剂，通过一步热聚合技术制备。此外，成功合成了具有不同重量比的磷掺杂（x  = 1、2 和 3 wt%）的 PgCN-x，并评估了它们的结构和形态特性。开发的修饰电极用于使用循环伏安法 (CV) 和差分脉冲伏安法 (DPV) 技术测定槲皮素 (QCN)。CV 和 DPV 研究验证特征峰ca。分别为 +0.20 和 +0.93 V（相对于 GCE）。值得注意的是，PgCN-3 催化剂的催化活性提高了，比原始 gCN 高 2 倍，这可能是由于高磷含量。优化条件下的定量分析显示，在 0.025 至 212.2 µM 的浓度范围内可全面检测 QCN，最低检测限为 1 nM。有趣的是，阻抗谱结果揭示了一条额外的明显信息，通过在存在带负电荷的氧化还原对的情况下与原始 gCN 进行比较来揭示 P 掺杂。目前开发的电化学方法已成功用于测定市售果汁样品中的 QCN，其回收率约为 95%。