ENVR 134 |
| The utilization of core-shell composite nanoparticles as a nano-sensing system to detect heavy metals has received much attention. In this study, SiO2/Au core-shell nanoparticles immobilized with urease as a nano-sensing element to detect heavy metals were fabricated. The monodisperse silica colloids were first obtained by the hydrolytic sol-gel method. The particle surfaces were then covered with gold shell by the reduction of chloroauric acid in the presence of sodium citrate. SEM and TEM images confirmed the fabrication of a 168 nm core with 55 nm gold shell, resulting in creating a 527 nm absorption peak. Moreover, urease and FITC were further immobilized on the gold surface by self-assembled monolayer. Several metal ions including Cu, Pb and Ni were examined. The dynamic ranges of the biosensor for metal ions were 2-3 orders-of-magnitude. Also, the sensitivity of the biosensor followed the order Cu>Ni>Pb. The limits of detection were 16nM for Cu. Results obtained in this study show good analytical performance for heavy metal determination in aqueous solution. |
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General Papers
6:00 PM-8:00 PM, Wednesday, August 22, 2007 BCEC -- Exhibit Hall - B2, Poster
Division of Environmental Chemistry |