基于三磷酸腺苷-L-半胱氨酸功能化纳米银比色法检测水中痕量Hg^(2+)

Colorimetric detection of Hg^(2+) using silver nanoparticles functionalized with ATP and L-Cys

基于L-半胱氨酸(L-Cys)和三磷酸腺苷(ATP)功能化的纳米银(AgNPs)建立了一种检测环境水样中Hg^(2+)的比色方法。L-Cys和ATP共同修饰的AgNPs(ATP-L-Cys-AgNPs),在水溶液中分散性良好,经紫外-可见光谱扫描显示在386 nm处有强吸收峰。在pH 9.5条件下,Hg^(2+)可与ATP-L-Cys-AgNPs发生配位反应,导致功能化AgNPs聚集,溶液由亮黄色转变为紫色,在554 nm处出现新的吸收峰,同时伴随着386 nm处吸收值下降。在最佳实验条件下,体系386 nm和554 nm处吸光度比值A386nm/A554nm的变化与Hg^(2+)浓度在1.3×10^(-7)~1.0×10^(-6)mol·L^(-1)范围内成线性关系,线性回归方程为ΔA386nm/A554nm=0.39c(0.1μmol·L^(-1))+0.86,相关系数r=0.9982,检出限为4.0×10-8 mol·L^(-1)。该方法简便、快捷、准确,可用于环境水样中Hg^(2+)含量的检测。

In this work,a new colorimetric strategy for the determination of Hg^(2+)in environmental water samples was proposed based on L-Cys and ATP functionalized silver nanoparticles(ATP-L-Cys-AgNPs).The prepared ATP-L-Cys-AgNPs had good dispersibility in aqueous solution and the ultraviolet-visible spectrum scan showed a strong absorption peak at 386 nm.In the presence of Hg^(2+),ATP-L-Cys-AgNPs exhibited a state change from dispersed to aggregated in pH 9.5 Tris-HAc buffer due to the special and strong coordination between ATP-L-Cys-AgNPs and Hg^(2+),the absorption peak at 386 nm decreased gradually and a new absorption peak at 554 nm correspondingly increased,and the color turned from bright yellow to red brown.Under the optimized conditions,the concentration of Hg2+in the range of 1.3×10^(-7)~1.0×10^(-6)mol·L^(-1)showed a good linear relationship with the change of the ratio of A386nm/A554nm of ATP-L-Cys-AgNPs.The regression equation wasΔA386nm/A554nm=0.39c(0.1μmol·L^(-1))+0.86,r=0.9982.The limit of detection(LOD)was 40 nM.The method also showed good precision and high repeatability in determining Hg^(2+)in real water samples such as pond water,tap water and river water.