纳米金反团聚的水中汞离子比色检测

Colorimetric detection of Hg^(2+) in water based on anti-aggregation of gold nanoparticles

以纳米金胶体作为检测工具,可以建立一种简单、快捷、灵敏度高的水中汞离子检测方法.其做法是:使用柠檬酸钠为还原剂合成酒红色的纳米金胶体,加入4’4联吡啶(Dpy)将纳米金颗粒聚集在一起,纳米金胶体的颜色会变化为蓝黑色.若水中没有汞离子,纳米金颗粒会保持团聚状态,颜色不变;若水中含有汞离子,则纳米金颗粒会发生反团聚现象,再次分散于水中,混合溶液的颜色变回酒红色.通过观察混合溶液的颜色变化,来判断水中是否含有汞离子,实现水中汞离子的检测.同时对不同浓度汞离子样品的紫外-可见吸收光谱进行分析,可以看出吸光度比值(A520/A640)与汞离子浓度之间呈现良好的线性度,并计算得到本方法的水中汞离子检测极限为54nmol/L(3δ).通过汞离子样品与其他多个离子样品的对比实验,证明本测试方法对汞离子的高选择性.本方法可用于水中汞离子的快速实时检测.

A simple,fast and sensitive method for the detection of mercury ions in water by using gold nanoparticles（AuNPs）was established.The color of the AuNPs solution synthesized by using sodium citrate was red.After adding 4,4-dipyridyl to the solution,AuNPs aggregated and its color changed into dark blue.If there was Hg2＋in water,AuNPs would disperse and its color would turn back to red.The UV-vis absorption spectra of different concentrations of Hg2＋showed good linearity between A520/A640 and the concentration of Hg2＋;and this method had a detection limit of 54nmol/L（3δ）.The specification experiment of a series of different metal ions showed high selectivity.The proposed method can be used for the fast detection of mercury ions in water,and is suitable for real-time detection as well.