Abstract In this paper, polymer dots (Pdots) were synthesized by one-step nanoprecipitation method from cationic conjugated polymer and hyaluronic acid, it was found that the fluorescence of Pdots could be reversibly quenched by NaClO. Mechanism study indicated that the reversible quenching was resulted from the reversible surface redox process of Pdots with NaClO and antioxidants. Based on this phenomenon, a reusable determination strategy of total antioxidant capacity (TAC) was developed. Three nonenzymatic antioxidants and two enzymatic antioxidants were selected as model targets to test its detection ability, and the detection linear ranges are 0.1–50 μM for glutathione and ascorbic acid, 0.5–10 μM for N-acetyl- l -cysteine, 1–30 U mL−1 for superoxide dismutase and 1–20 U mL−1 for catalase. Compared with standard assay method of total antioxidant capacity, this Pdots-NaClO system simplified operation process and meanwhile increased sensitivity. Moreover, this strategy has a great potential in the assay of food quality, as it was successfully applied to investigate TAC in fruit and tea samples with satisfactory recoveries ranging from 88.4% to 114.2%, and the relative standard deviation of the obtained TAC value was from 3.2% to 9.9%.

中文翻译：

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用于测定食品样品中总抗氧化能力的聚合物点的可逆表面氧化还原

摘要 本文以阳离子共轭聚合物和透明质酸为原料，通过一步纳米沉淀法合成了聚合物点（Pdots），发现Pdots的荧光可以被NaClO可逆猝灭。机理研究表明，可逆淬灭是由 Pdots 与 NaClO 和抗氧化剂的可逆表面氧化还原过程引起的。基于这种现象，开发了一种可重复使用的总抗氧化能力（TAC）测定策略。选择三种非酶促抗氧化剂和两种酶促抗氧化剂作为模型靶标来测试其检测能力，检测线性范围为谷胱甘肽和抗坏血酸的检测线性范围为 0.1-50 μM，N-乙酰-l-半胱氨酸的检测线性范围为 0.5-10 μM，1-30超氧化物歧化酶为 U mL-1，过氧化氢酶为 1-20 U mL-1。与标准的总抗氧化能力测定方法相比，该Pdots-NaClO系统简化了操作过程，同时提高了灵敏度。此外，该策略在食品质量检测方面具有巨大潜力，因为它成功应用于水果和茶样品中 TAC 的研究，回收率从 88.4% 到 114.2% 不等，获得的 TAC 值的相对标准偏差为从 3.2% 到 9.9%。