Control of the surface charges of Au-Ag nanorods: Selective detection of iron in the presence of poly(sodium 4-styrenesulfonate)

Yu Fen Huango, Yang Wei Lin, Huan Tsung Chang

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

In this article, we report a simple approach for selectively sensing Fe2+ ions using CTAB-stabilized Au-Ag nanorods (CTAB-Au-Ag NRs) in the presence of poly(sodium 4-styrenesulfonate) (PSS). The prepared CTAB-Au-Ag NRs exhibit an intense longitudinal surface plasmon resonance absorption (>109 M-1 cm-1 at 827 nm) in the near-infrared region. As a result of attractive electrostatic interactions between PSS and CTAB, agglomeration of the CTAB-Au-Ag NRs induces a change in the absorption at 827 nm. From £potential measurements, we found that the degree of agglomeration was highly dependent on the surface charge density of the CTAB-Au-Ag NRs. Because Fe2+ (Fe3+) ions selectively interact with PSS, the degree of agglomeration-and, thus, the change in absorption at 827 nm-is dependent on the concentration of Fe2+ (Fe3+) ions. To improve the selectivity of the present sensing system, Fe3+ ions were reduced to Fe2+ ions in the presence of ascorbic acid prior to analysis. The concentrations of CTAB-Au-Ag NRs and PSS are both important parameters in determining the sensitivity and selectivity of the present approach toward sensing Fe2+ ions. Under the optimum conditions [34 pM CTAB-Au-Ag NRs, (5 × 10-6)% PSS, pH 7.2], the limit of detection for Fe2+ ions at a signal-to-noise ratio of 3 was 1.0μM. We applied this nanosensor system to the determination of Fe2+ in ferritin and in aqueous environmental samples; this approach has the advantages of simplicity, accuracy, and precision (the relative standard deviation from five runs with each sample was below 3%).

Original languageEnglish
Pages (from-to)12777-12781
Number of pages5
JournalLangmuir
Volume23
Issue number25
DOIs
Publication statusPublished - 2007 Dec 4

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All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

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