Citrate-Capped Platinum Nanoparticle as a Smart Probe for Ultrasensitive Mercury Sensing

作者：Gang-Wei Wu, Shao‐Bin He, Hua‐Ping Peng, Hao‐Hua Deng, Ai‐Lin Liu, Xinhua Lin, Xing‐Hua Xia, Wei Chen · 发表于：Analytical Chemistry · 年份：2014 · DOI：10.1021/ac503544w · 被引用次数：287 · 研究领域：Advanced Nanomaterials in Catalysis、Advanced biosensing and bioanalysis techniques、Mercury impact and mitigation studies

An easily prepared platinum nanoparticle (PtNP) probe for the sensitive and selective detection of Hg(2+) ions is developed here. The PtNPs with an average size of approximately 2.5 nm were prepared by a reduction method with sodium borohydride and trisodium citrate serving as reductant and stabilizer, respectively. The resulting PtNPs could catalyze the reduction of Hg(2+) by surface-capping citrate. The effect of Hg(2+) uptake implies amalgam formation, which leads to remarkable inhibition of the peroxidase-like activity of citrate-capped PtNPs. On the basis of this effect, a colorimetric mercury sensor was established through the use of citrate-capped PtNPs to catalyze the colorimetric system of 3,3',5,5'-tetramethylbenzidine (TMB) and H2O2. The high specificity of the Hg-Pt interaction provides the excellent selectivity for Hg(2+) over interfering metal ions. The sensitivity of this smart probe to Hg(2+) is extremely excellent with a limit of detection (LOD) as low as 8.5 pM. In view of these advantages, as well as the cost-effectiveness, minimized working steps, and naked-eye observation, we expect that this colorimetric sensor will be a promising candidate for the field detection of toxic Hg(2+) ions in environmental, biological, and food samples.