金纳米比色检测铅.pdfVIP

Biosensors and Bioelectronics 25 2010 984–989 Contents lists available at ScienceDirect Biosensors and Bioelectronics j o u rn al h omepage: w w w. elsev /locate/bios Sensitivity enhancement in the colorimetric detection of lead II ion using gallic acid–capped gold nanoparticles: Improving size distribution and minimizing interparticle repulsion Kuan-Wei Huang a , Cheng-Ju Yu a , Wei-Lung Tseng a,b,? a Department of Chemistry, National Sun Yat-sen University, Taiwan b National Sun Yat-sen University-Kaohsiung Medical University Joint Research Center, Kaohsiung, Taiwan a r t i c l e i n f o a b s t r a c t Article history: We have developed a colorimetric assay for the highly sensitive and selective detection of Pb2+ by Received 6 June 2009 narrowing the size distribution of gallic acid–capped gold nanoparticles GA–AuNPs and minimizing Received in revised form 2 September 2009 electrostatic repulsion between each GA–AuNP. We unveil that the particle size and size distribution of Accepted 3 September 2009 GA–AuNPs could be controlled by varying the pH of HAuCl4 with ?xed concentrations of HAuCl4 and GA. Available online 8 September 2009 When the pH of the precursor solution i.e., HAuCl4 was adjusted from 2.2 to 11.1, the average diam- eter of GA–AuNPs was decreased from 75.1 nm to 9.3 nm and their size distribution was reduced from Keywords: 2+ 56.6?93.6 nm to 9.0?9.6 nm. The colorimetric sensitivity of the Pb -induced aggregation of GA–AuNPs Gold nanoparticles Colorimetric detection could be improved using narrow size distribution of GA–AuNPs. Moreover, further enhancement of the Gallic acid colorimetric sensitivity of GA–AuNPs toward Pb2+ could be achieved by adding NaClO4 to minimize elec- Lead ions trostatic repulsion between GA–AuNPs, which provide a small energy barrier for Pb2+ to overcome. Under Sensor the optimum conditions 1.0 mM NaClO4 and 20 mM formic acid at pH 4.5 , the select