title: Exploring the interactions between gold nanoparticles and analytes through surface-assisted laser desorption/ionization mass spectrometry.
abstract: Surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) is applied to provide strong evidence for the chemical reactions of functionalized gold nanoparticles (Au NPs) with analytes--Hg(2+) ions induced MPA-Au NPs aggregation in the presence of 2,6-pyridinedicarboxylic acid (PDCA) and H(2)O(2) induced fluorescence quenching of 11-MUA-Au NDs. PDCA-Hg(2+)-MPA coordination is responsible for Au NPs aggregation, while the formation of 11-MUA disulfide compounds that release into the bulk solution is responsible for H(2)O(2)-induced fluorescence quenching. In addition to providing information about the chemical structures, SALDI-MS is also selective and sensitive for the detection of Hg(2+) ions and H(2)O(2). The limits of detection (LODs) for Hg(2+) ions and H(2)O(2) by SALDI-MS were 300 nM and 250 microM, respectively. The spot-to-spot variations in the two studies were both less than 18% (50 sample spots). Our results reveal that SALDI-MS can be used to study analyte-induced changes in the surface properties of nanoparticles.
authors.affiliation: Department of Chemistry, National Taiwan University, Taipei, Taiwan.
authors.forename: Yang-Wei
authors.initials: YW
authors.lastname: Lin
authors.forename: Wen-Tsen
authors.initials: WT
authors.lastname: Chen
authors.forename: Huan-Tsung
authors.initials: HT
authors.lastname: Chang