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Fabrication and evolution of multilayer silver nanofilms for surface-enhanced Raman scattering sensing of arsenate.

Hao J, Han MJ, Xu Z, Li J, Meng X - Nanoscale Res Lett (2011)

Bottom Line: The SERS spectra of arsenate showed that characteristic SERS bands of arsenate appear at approximately 780 and 420 cm-1, and the former possesses higher SERS intensity.By comparing the peak heights of the approximately 780 cm-1 band of the SERS spectra, the optimal Ag/GL substrate has been obtained for the most sensitive SERS sensing of arsenate.Using this optimal substrate, the limit of detection (LOD) of arsenate was determined to be approximately 5 μg·l-1.

View Article: PubMed Central - HTML - PubMed

Affiliation: Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ 07030, USA. xmeng@stevens.edu.

ABSTRACT
Surface-enhanced Raman scattering (SERS) has recently been investigated extensively for chemical and biomolecular sensing. Multilayer silver (Ag) nanofilms deposited on glass slides by a simple electroless deposition process have been fabricated as active substrates (Ag/GL substrates) for arsenate SERS sensing. The nanostructures and layer characteristics of the multilayer Ag films could be tuned by varying the concentrations of reactants (AgNO3/BuNH2) and reaction time. A Ag nanoparticles (AgNPs) double-layer was formed by directly reducing Ag+ ions on the glass surfaces, while a top layer (3rd-layer) of Ag dendrites was deposited on the double-layer by self-assembling AgNPs or AgNPs aggregates which had already formed in the suspension. The SERS spectra of arsenate showed that characteristic SERS bands of arsenate appear at approximately 780 and 420 cm-1, and the former possesses higher SERS intensity. By comparing the peak heights of the approximately 780 cm-1 band of the SERS spectra, the optimal Ag/GL substrate has been obtained for the most sensitive SERS sensing of arsenate. Using this optimal substrate, the limit of detection (LOD) of arsenate was determined to be approximately 5 μg·l-1.

No MeSH data available.


Related in: MedlinePlus

Histograms indicating the change in peak heights of the 780 cm-1 band with reaction time. The peak heights were measured from the SERS spectra of 200 μg·l-1 arsenate on the Ag/GL substrates prepared in (A) 1/0.5 mM, (B) 5/2.5 mM, and (C) 10/5 mM AgNO3/BuNH2 ethanolic solutions with different reaction times.
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Figure 5: Histograms indicating the change in peak heights of the 780 cm-1 band with reaction time. The peak heights were measured from the SERS spectra of 200 μg·l-1 arsenate on the Ag/GL substrates prepared in (A) 1/0.5 mM, (B) 5/2.5 mM, and (C) 10/5 mM AgNO3/BuNH2 ethanolic solutions with different reaction times.

Mentions: Figure 4B shows the SERS spectra of arsenate (200 μg·l-1) on the Ag/GL substrates prepared in 5/2.5 mM AgNO3/BuNH2 solution at different reaction times of 2, 3.5, 5, 9, 18, 25, 31, and 40 h, respectively. It was of particular interest that the Ag/GL-5/2.5-18 as a SERS substrate gave the most intense arsenate peak among all eight Ag/GL substrates, while the peaks from Ag/GL-5/2.5-2 and Ag/GL-5/2.5-40 substrates were extremely weak. This clearly reflects the effect of the preparation conditions on the SERS sensitivity of the substrates. In order to more distinctly illustrate the results mentioned above, the peak heights of the arsenate Raman bands were plotted against the reaction time to yield a histogram (Figure 5B). From the figure, we can see that as the reaction time was prolonged from 2 to 40 h, the peak height increased gradually until a maximum appeared, and then decreased. The maximum peak height was obtained from the Ag/GL-5/2.5-18 substrate.


Fabrication and evolution of multilayer silver nanofilms for surface-enhanced Raman scattering sensing of arsenate.

Hao J, Han MJ, Xu Z, Li J, Meng X - Nanoscale Res Lett (2011)

Histograms indicating the change in peak heights of the 780 cm-1 band with reaction time. The peak heights were measured from the SERS spectra of 200 μg·l-1 arsenate on the Ag/GL substrates prepared in (A) 1/0.5 mM, (B) 5/2.5 mM, and (C) 10/5 mM AgNO3/BuNH2 ethanolic solutions with different reaction times.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211326&req=5

Figure 5: Histograms indicating the change in peak heights of the 780 cm-1 band with reaction time. The peak heights were measured from the SERS spectra of 200 μg·l-1 arsenate on the Ag/GL substrates prepared in (A) 1/0.5 mM, (B) 5/2.5 mM, and (C) 10/5 mM AgNO3/BuNH2 ethanolic solutions with different reaction times.
Mentions: Figure 4B shows the SERS spectra of arsenate (200 μg·l-1) on the Ag/GL substrates prepared in 5/2.5 mM AgNO3/BuNH2 solution at different reaction times of 2, 3.5, 5, 9, 18, 25, 31, and 40 h, respectively. It was of particular interest that the Ag/GL-5/2.5-18 as a SERS substrate gave the most intense arsenate peak among all eight Ag/GL substrates, while the peaks from Ag/GL-5/2.5-2 and Ag/GL-5/2.5-40 substrates were extremely weak. This clearly reflects the effect of the preparation conditions on the SERS sensitivity of the substrates. In order to more distinctly illustrate the results mentioned above, the peak heights of the arsenate Raman bands were plotted against the reaction time to yield a histogram (Figure 5B). From the figure, we can see that as the reaction time was prolonged from 2 to 40 h, the peak height increased gradually until a maximum appeared, and then decreased. The maximum peak height was obtained from the Ag/GL-5/2.5-18 substrate.

Bottom Line: The SERS spectra of arsenate showed that characteristic SERS bands of arsenate appear at approximately 780 and 420 cm-1, and the former possesses higher SERS intensity.By comparing the peak heights of the approximately 780 cm-1 band of the SERS spectra, the optimal Ag/GL substrate has been obtained for the most sensitive SERS sensing of arsenate.Using this optimal substrate, the limit of detection (LOD) of arsenate was determined to be approximately 5 μg·l-1.

View Article: PubMed Central - HTML - PubMed

Affiliation: Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ 07030, USA. xmeng@stevens.edu.

ABSTRACT
Surface-enhanced Raman scattering (SERS) has recently been investigated extensively for chemical and biomolecular sensing. Multilayer silver (Ag) nanofilms deposited on glass slides by a simple electroless deposition process have been fabricated as active substrates (Ag/GL substrates) for arsenate SERS sensing. The nanostructures and layer characteristics of the multilayer Ag films could be tuned by varying the concentrations of reactants (AgNO3/BuNH2) and reaction time. A Ag nanoparticles (AgNPs) double-layer was formed by directly reducing Ag+ ions on the glass surfaces, while a top layer (3rd-layer) of Ag dendrites was deposited on the double-layer by self-assembling AgNPs or AgNPs aggregates which had already formed in the suspension. The SERS spectra of arsenate showed that characteristic SERS bands of arsenate appear at approximately 780 and 420 cm-1, and the former possesses higher SERS intensity. By comparing the peak heights of the approximately 780 cm-1 band of the SERS spectra, the optimal Ag/GL substrate has been obtained for the most sensitive SERS sensing of arsenate. Using this optimal substrate, the limit of detection (LOD) of arsenate was determined to be approximately 5 μg·l-1.

No MeSH data available.


Related in: MedlinePlus