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Published on: February 28, 2015
A colorimetric nitrite detection system with excellent selectivity and high sensitivity based on Ag@Au nanoparticles
Tianhua Li1, Yonglong Li, Yujie Zhang
1Key Laboratory of Magnetic Materials and Devices, & Division of Functional Materials and Nano Devices, Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201, China. aiguo@nimte.ac.cn shenzheyu@nimte.ac.cn.
A new, cost-effective detection system using silver-gold nanoparticles (Ag@AuNPs) offers sensitive and selective detection of nitrite ions (NO2(-)). This visual method provides a lower limit of detection than previously reported, enabling rapid environmental monitoring.
Area of Science:
- Environmental Science
- Analytical Chemistry
- Materials Science
Background:
- Nitrite ion (NO2(-)) is a significant environmental pollutant with health implications.
- Existing methods for NO2(-) detection are often complex and costly.
- Development of sensitive, selective, and affordable detection techniques is crucial.
Purpose of the Study:
- To develop an improved and cost-effective NO2(-) detection system.
- To utilize a redox etching strategy with CTAB-stabilized Ag-Au core-shell nanoparticles (Ag@AuNPs).
- To enable rapid, visual, and quantitative detection of NO2(-) in environmental samples.
Main Methods:
- Synthesis and characterization of CTAB-stabilized Ag-Au core-shell nanoparticles (Ag@AuNPs).
- Utilizing a redox etching strategy for NO2(-) detection.
- Verification of the detection mechanism using UV-Vis spectroscopy, TEM, and XPS.
- Testing selectivity against various common ions and anions.
- Determining the limit of detection (LOD) and linear range for quantitative analysis.
Main Results:
- The Ag@AuNP system exhibits a distinct color change (purple to colorless) in response to NO2(-).
- Excellent selectivity for NO2(-) was observed over a wide range of interfering ions.
- The limit of detection (LOD) by visual inspection is 1.0 μM, surpassing previous methods.
- UV-Vis spectroscopy achieved an even lower LOD of 0.1 μM.
- A good linear relationship was established for quantitative analysis within the 1.0–20.0 μM range.
- Successful application in analyzing NO2(-) in real water samples (tap and lake water).
Conclusions:
- The developed Ag@AuNP-based system provides a rapid and sensitive method for NO2(-) detection.
- The system offers high selectivity and a low visual LOD, making it suitable for field applications.
- This approach represents a significant advancement for environmental monitoring of nitrite ions.
