1. Folic acid capping Bi 3+ -doped Ag quantum dots for enzyme-like dual-mode recognition of toxic S 2- and visual sensing of NO 2 .
- Author
-
Feng J, Feng L, Sun S, Wang X, Zhi H, Shang R, Yang Y, Wang L, Yan Z, and Hu L
- Subjects
- Nitrites analysis, Nitrites chemistry, Hydrogen Peroxide chemistry, Humans, Benzidines chemistry, Limit of Detection, Oxidation-Reduction, Quantum Dots chemistry, Folic Acid chemistry, Silver chemistry
- Abstract
Background: NO
2 - and S2- 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 NO2 - or S2- , i.e., infantile methemoglobin, cancer and even to death. Although tremendous efforts have been afforded to monitor NO2 - and S2- , 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 S2- and NO2 - in practice., Results: A kind of folic acid capping Bi3+ -doped Ag quantum dots (FA@Bi3+ -Ag QDs) was developed for the first time by one-pot homogeneous reduced self-assembly. Not only did FA@Bi3+ -Ag QDs possess intrinsic fluorescent property, it expressed synergistic peroxidase-like activity to catalyze the redox of 3,3',5,5'-tetramethylbenzidine (TMB) and H2 O2 with Km /vmax of 0.087 mM/6.61 × 10-8 M s-1 and 6.42 mM/6.25 × 10-7 M s-1 respectively. Interestingly, trace S2- could exclusively alter its fluorescent property and peroxidase-like activity, exhibiting significant hypochromic and "turn-on" fluorescent effects. While trace NO2 - could make FA@Bi3+ -Ag QDs-TMB-H2 O2 system hyperchromic. Under the optimized conditions, FA@Bi3+ -Ag QDs were applied for dual-mode recognition of S2- and visual sensing of NO2 - in real food samples with satisfactory recoveries, i.e., 100.7-107.9 %/95.8-104.7 % and 97.2-104.8 % respectively. The synergistic enzyme-mimic mechanism of FA@Bi3+ -Ag QDs and its selective response mechanisms to S2- and NO2 - were also proposed., Significance: This represents the first nanozyme-based FA@Bi3+ -Ag QDs system for dual-mode recognition of S2- and visual sensing of NO2 - , 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., Competing Interests: Declaration of competing interest The authors declare no competing financial interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)- Published
- 2024
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