Facile colorimetric detection of Hg2+ based on anti-aggregation of silver nanoparticles

• DOI: 10.1016/j.bios.2014.02.007
• Publication Date: 2014-02-14T11:46:14Z
• Authors: Junling Duan; Hongzong Yin; Ranran Wei; Weiwei Wang
• Keywords: Silver; Cations, Divalent; Limit of Detection; Nanoparticles; Colorimetry; Mercury; Thioguanine; 01 natural sciences; Water Pollutants, Chemical; 6. Clean water; 0104 chemical sciences

This paper describes an investigation of a facile colorimetric sensor for Hg(2+) in aqueous solution based on the anti-aggregation of silver nanoparticles (AgNPs). In the absence of Hg(2+), the addition of 6-Thioguanine to AgNPs solution led to the aggregation of AgNPs, resulting in a color change from yellow to brown with a red shift of absorption spectra. However, the presence of Hg(2+) inhibited the 6-Thioguanine-induced aggregation of AgNPs accompanying with a color change from brown to yellow. Under the optimal conditions, the ratio between the absorbance at 530 nm and 394 nm (A530/A394) was linearly proportional to the Hg(2+) concentration in a range from 0 to 333 nM with a detection limit of 4 nM. Other environmentally relevant metal ions did not interfere with the detection of Hg(2+). The proposed method was simple, cost-effective and rapid without any complicated modifying step. It was successfully applied to detect Hg(2+) in environmental water samples.