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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

Typical SERS spectra of arsenate using various Ag/GL substrates as active substrates. (A) SERS spectra of arsenate: (a) 0 μg·l-1 (background) and (b) 300 μg·l-1 on Ag/GL-1/0.5-25 substrate; and (c) 0 μg·l-1 (background) and (d) 250 μg·l-1 on Ag/GL-5/2.5-18 substrate. (B) SERS spectra of 200 μg·l-1 arsenate on various Ag/GL substrates prepared in 5/2.5 mM AgNO3/BuNH2 ethanolic solution at different reaction times: (a) 2 h, (b) 3.5 h, (c) 5 h, (d) 9 h, (e) 18 h, (f) 25 h, (g) 31 h, and (h) 40 h. The samples were air-dried before SERS measurements. The spectra were shifted vertically for clarity but the relative intensity was kept unchanged except for the curve a in (B).
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Figure 4: Typical SERS spectra of arsenate using various Ag/GL substrates as active substrates. (A) SERS spectra of arsenate: (a) 0 μg·l-1 (background) and (b) 300 μg·l-1 on Ag/GL-1/0.5-25 substrate; and (c) 0 μg·l-1 (background) and (d) 250 μg·l-1 on Ag/GL-5/2.5-18 substrate. (B) SERS spectra of 200 μg·l-1 arsenate on various Ag/GL substrates prepared in 5/2.5 mM AgNO3/BuNH2 ethanolic solution at different reaction times: (a) 2 h, (b) 3.5 h, (c) 5 h, (d) 9 h, (e) 18 h, (f) 25 h, (g) 31 h, and (h) 40 h. The samples were air-dried before SERS measurements. The spectra were shifted vertically for clarity but the relative intensity was kept unchanged except for the curve a in (B).

Mentions: Figure 4A shows typical background spectra (curves (a) and (c)) and SERS spectra of arsenate (curves (b) and (d)) on the Ag/GL-1/0.5-25 and Ag/GL-5/2.5-18 substrates, respectively. In the background spectrum (curve (a) in Figure 4A) of the Ag/GL-1/0.5-25 prepared in lower concentrations of AgNO3/BuNH2, there existed some Raman bands in the range of 300 to 1200 cm-1. Their intensities varied depending on the preparation conditions of the Ag films. When the higher concentrations of AgNO3/BuNH2 were used, the resulting Ag/GL-5/2.5-18 substrate had a simpler background spectrum (curve (c) in Figure 4A). Compared with the background spectrum of the Ag/GL-1/0.5-25, the intensities of two Raman bands centered at 1046 ± 8 cm-1 and 688 ± 3 cm-1 are much higher, while the other bands diminished or even disappeared.


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)

Typical SERS spectra of arsenate using various Ag/GL substrates as active substrates. (A) SERS spectra of arsenate: (a) 0 μg·l-1 (background) and (b) 300 μg·l-1 on Ag/GL-1/0.5-25 substrate; and (c) 0 μg·l-1 (background) and (d) 250 μg·l-1 on Ag/GL-5/2.5-18 substrate. (B) SERS spectra of 200 μg·l-1 arsenate on various Ag/GL substrates prepared in 5/2.5 mM AgNO3/BuNH2 ethanolic solution at different reaction times: (a) 2 h, (b) 3.5 h, (c) 5 h, (d) 9 h, (e) 18 h, (f) 25 h, (g) 31 h, and (h) 40 h. The samples were air-dried before SERS measurements. The spectra were shifted vertically for clarity but the relative intensity was kept unchanged except for the curve a in (B).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 4: Typical SERS spectra of arsenate using various Ag/GL substrates as active substrates. (A) SERS spectra of arsenate: (a) 0 μg·l-1 (background) and (b) 300 μg·l-1 on Ag/GL-1/0.5-25 substrate; and (c) 0 μg·l-1 (background) and (d) 250 μg·l-1 on Ag/GL-5/2.5-18 substrate. (B) SERS spectra of 200 μg·l-1 arsenate on various Ag/GL substrates prepared in 5/2.5 mM AgNO3/BuNH2 ethanolic solution at different reaction times: (a) 2 h, (b) 3.5 h, (c) 5 h, (d) 9 h, (e) 18 h, (f) 25 h, (g) 31 h, and (h) 40 h. The samples were air-dried before SERS measurements. The spectra were shifted vertically for clarity but the relative intensity was kept unchanged except for the curve a in (B).
Mentions: Figure 4A shows typical background spectra (curves (a) and (c)) and SERS spectra of arsenate (curves (b) and (d)) on the Ag/GL-1/0.5-25 and Ag/GL-5/2.5-18 substrates, respectively. In the background spectrum (curve (a) in Figure 4A) of the Ag/GL-1/0.5-25 prepared in lower concentrations of AgNO3/BuNH2, there existed some Raman bands in the range of 300 to 1200 cm-1. Their intensities varied depending on the preparation conditions of the Ag films. When the higher concentrations of AgNO3/BuNH2 were used, the resulting Ag/GL-5/2.5-18 substrate had a simpler background spectrum (curve (c) in Figure 4A). Compared with the background spectrum of the Ag/GL-1/0.5-25, the intensities of two Raman bands centered at 1046 ± 8 cm-1 and 688 ± 3 cm-1 are much higher, while the other bands diminished or even disappeared.

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