Xu Yunbo, Dong Yangjun, Jiang Xue, Zhu Ningning
Department of Chemistry, College of Life and Environment Sciences, Shanghai Normal University, Shanghai 200234, China.
J Nanosci Nanotechnol. 2013 Oct;13(10):6820-5. doi: 10.1166/jnn.2013.7785.
This study describes a simple and highly selective method for the colorimetric detection of trivalent chromium (Cr3+) using tartrate-capped silver nanoparticles (AgNPs) as probe. The addition of tartrate to the initially prepared AgNPs gives tartrate-stabilized AgNPs ascribing to the electrostatic repulsion of the highly negatively charged tartrate ions covered on the surface of AgNPs. It is found that, in the presence of Cr3+ in aqueous solution, the aggregation of tartrate-stabilized AgNPs occurs. The color of AgNPs suspension changes from yellow to pink and the surface plasmon absorption band broadens and red shifts, which could be applied for the colorimetric detection of Cr3+ in aqueous solution. The utilization of tartrate-stabilized AgNPs as probe substantially increases the selectivity and sensitivity for colorimetric detection of Cr3+. Control experiments with the addition of over 14 other metal ions, such as Pb2+, Zn2+, Cr2O7(2-), Cd2+, Co2+, Cu2+, Al3+, Ni2+, Mn2+, Ba2+, Fe3+, Ca2+, Mg2+, Sr+ do not result in a distinct change in the color or in the spectrum of the suspension, indicating that these metal ions do not interfere with the colorimetric detection of Cr3+. Under the conditions employed here, A502/A393 (ratio of absorption value at 502 nm to 393 nm) is linear with the concentration of Cr3+ within a concentration range from 0.1 to 1.17 microM with a detection limit of 0.06 microM. This study may offer a simple, rapid and sensitive approach to colorimetric detection of Cr3+ in aqueous solution.
本研究描述了一种简单且高选择性的比色法，该方法使用酒石酸盐包覆的银纳米颗粒（AgNPs）作为探针来检测三价铬（Cr3+）。向最初制备的AgNPs中加入酒石酸盐，由于覆盖在AgNPs表面的带高负电荷的酒石酸根离子的静电排斥作用，得到了酒石酸盐稳定的AgNPs。研究发现，在水溶液中存在Cr3+的情况下，酒石酸盐稳定的AgNPs会发生聚集。AgNPs悬浮液的颜色从黄色变为粉红色，表面等离子体吸收带变宽并发生红移，这可用于水溶液中Cr3+的比色检测。使用酒石酸盐稳定的AgNPs作为探针大大提高了Cr3+比色检测的选择性和灵敏度。添加超过14种其他金属离子（如Pb2+、Zn2+、Cr2O7(2-)、Cd2+、Co2+、Cu2+、Al3+、Ni2+、Mn2+、Ba2+、Fe3+、Ca2+、Mg2+、Sr+）的对照实验并未导致悬浮液的颜色或光谱发生明显变化，表明这些金属离子不会干扰Cr3+的比色检测。在本文采用的条件下，A502/A393（502 nm处的吸收值与393 nm处的吸收值之比）与Cr3+浓度在0.1至1.17 microM的浓度范围内呈线性关系，检测限为0.06 microM。本研究可能为水溶液中Cr3+的比色检测提供一种简单、快速且灵敏的方法。
