基于羟基氧化钴纳米片的比色和荧光双模法检测砷(Ⅴ)

Colorimetric and fluorescence dual-mode detection of arsenic(Ⅴ)based on cobalt oxyhydroxide nanoplates

羟基氧化钴(CoOOH)纳米片的类氧化酶活性因为体系中的As(Ⅴ)被抑制,从而减弱CoOOH纳米片对对苯二胺(PPD)的氧化,溶液吸光度发生变化。基于以上原理,结合对苯二胺氧化物(oxPPD)对染料吖啶橙(AO)的荧光内滤效应(IFE),建立了一种比色和荧光双模法用于As(Ⅴ)的定量检测。考察了不同浓度As(Ⅴ)的吸光度和荧光强度变化规律,并对CoOOH纳米片浓度、 PPD浓度、缓冲液pH、反应温度等条件进行了优化。结果表明:在优化条件下,As(Ⅴ)浓度与相应信号强度具有良好的线性关系,比色法和荧光法的检出限分别为5和4 nmol/L。该方法已用于市中心湖水中As(Ⅴ)的测定。

The oxidase-like activity of cobalt oxyhydroxide(CoOOH)nanosheets is inhibited by arsenic(Ⅴ)in the system,thereby attenuating the oxidation of p-phenylenediamine(PPD)by CoOOH nanosheets,and changing the absorbance of the solution.Based on this principle,and the fluorescence inner filter effect(IFE)of p-phenylenediamine oxide(oxPPD)on the dye acridine orange(AO),a colorimetric and fluorescence dualmode method for the quantitative detection of As(Ⅴ)was established.The variation of absorbance and fluorescence intensity of As(Ⅴ)with different concentrations was investigated,and the effects of the concentrations of CoOOH nanosheet and PPD,pH of buffer solution,and temperature of reaction were optimized.The results showed that under the optimized conditions,the concentration of As(Ⅴ)had a good linear relationship with the corresponding signal intensity,and the detection limits of colorimetric and fluorescence method were 5 and 10 nmol/L,respectively.The method has been used for the determination of arsenic(Ⅴ)in lake water located the city center.