NO and S are two kinds of common toxic anions widely distributed in environmental water, soil and food products. Human beings have suffered a lot of diseases from intake of excessive NO or S, ., infantile methemoglobin, cancer and even to death. Although tremendous efforts have been afforded to monitor NO and S, most were high instrument-depended with complex processing procedures. To keep food safety and to protect human health, it will be a huge challenge to develop a convenient and efficient way to monitor S and NO in practice. A kind of folic acid capping Bi-doped Ag quantum dots (FA@Bi-Ag QDs) was developed for the first time by one-pot homogeneous reduced self-assembly. Not only did FA@Bi-Ag QDs possess intrinsic fluorescent property, it expressed synergistic peroxidase-like activity to catalyze the redox of 3,3′,5,5′-tetramethylbenzidine (TMB) and HO with / of 0.087 mM/6.61 × 10 M s and 6.42 mM/6.25 × 10 M s respectively. Interestingly, trace S could exclusively alter its fluorescent property and peroxidase-like activity, exhibiting significant hypochromic and “turn-on” fluorescent effects. While trace NO could make FA@Bi-Ag QDs-TMB-HO system hyperchromic. Under the optimized conditions, FA@Bi-Ag QDs were applied for dual-mode recognition of S and visual sensing of NO in real food samples with satisfactory recoveries, ., 100.7–107.9 %/95.8–104.7 % and 97.2–104.8 % respectively. The synergistic enzyme-mimic mechanism of FA@Bi-Ag QDs and its selective response mechanisms to S and NO were also proposed. This represents the first nanozyme-based FA@Bi-Ag QDs system for dual-mode recognition of S and visual sensing of NO, well meeting the basic requirement in drinking water set by WHO. It will offer a promising way for multi-mode monitoring of different pollution using the same nanozyme-based sensor.

中文翻译：

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叶酸封端 Bi3+ 掺杂银量子点，用于有毒 S2− 的类酶双模式识别和 NO2− 的视觉传感


NO和S是两种常见的有毒阴离子，广泛分布于环境水、土壤和食品中。人类因摄入过多的NO或S、婴儿高铁血红蛋白、癌症甚至死亡而遭受了许多疾病。尽管人们为监测 NO 和 S 付出了巨大的努力，但大多数都高度依赖仪器且处理程序复杂。为了保证食品安全和保护人类健康，在实践中开发一种方便、高效的方法来监测S和NO将是一个巨大的挑战。首次通过一锅均质还原自组装技术开发了一种叶酸封端的双掺杂银量子点（FA@Bi-Ag QDs）。 FA@Bi-Ag QD 不仅具有固有的荧光特性，还表现出协同的过氧化物酶样活性，可催化 3,3',5,5'-四甲基联苯胺 (TMB) 和 H2O 的氧化还原，l 为 0.087 mM/6.61 ×分别为 10 M s 和 6.42 mM/6.25 × 10 M s。有趣的是，微量S可以专门改变其荧光特性和过氧化物酶样活性，表现出显着的减色和“开启”荧光效应。而微量NO可使FA@Bi-Ag QDs-TMB-HO体系增色。在优化条件下，FA@Bi-Ag QDs应用于实际食品样品中S的双模式识别和NO的视觉传感，回收率分别为100.7–107.9 %/95.8–104.7 %和97.2–104.8 %。 。还提出了 FA@Bi-Ag QDs 的协同酶模拟机制及其对 S 和 NO 的选择性响应机制。这是第一个基于纳米酶的FA@Bi-Ag QDs系统，用于S的双模式识别和NO的视觉传感，很好地满足了WHO对饮用水的基本要求。 它将为使用相同的基于纳米酶的传感器对不同污染进行多模式监测提供一种有前景的方法。