Annealing of Glass-Deposited Silver Island Films Lead to Creation of Regular Sers-Active Surfaces. Comparative Scanning Tunnel Microscopy and Sers Study

Маскевич, С. А.; Sveklo, I.; Feofanov, Alexei V.; Ianoul, Anatoli; Oleinikov, Vladimir; Федорова, О. М.; Громов, С. П.; Nabiev, Igor; Алфимов, М. В.; Kivach, L. N.

doi:10.1007/978-94-011-0371-8_11

Cited by 3 publications

(4 citation statements)

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“…High-temperature annealing of thick and island silver films was demonstrated to change the structure of metal surface roughness and to modify the SERS-active properties of these substrates. [6][7][8] Annealing may result in enhancement of the long-range electromagnetic component of the SERS effect, and it increases stability of the silver films to organic solvents. 6,8 Separating analyte molecules from the metal surface by a monolayer of spacer molecules has been proposed to prevent metal-induced perturbation of electronic structure and/or conformation of an analyte.…”

Section: Introductionmentioning

confidence: 99%

“…[6][7][8] Annealing may result in enhancement of the long-range electromagnetic component of the SERS effect, and it increases stability of the silver films to organic solvents. 6,8 Separating analyte molecules from the metal surface by a monolayer of spacer molecules has been proposed to prevent metal-induced perturbation of electronic structure and/or conformation of an analyte. In this case, either self-adsorption of spacer molecules on hydrosol particles 9,10 or transfer of a spacer monolayer to the metal electrode or quartz (glass) plate with metal island films by means of Langmuir-Blodgett or Langmuir-Schaefer techniques 8,11,12 can be employed.…”

Section: Introductionmentioning

confidence: 99%

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Surface-Enhanced Raman Scattering (SERS) Study of Mercaptoethanol Monolayer Assemblies on Silver Citrate Hydrosol. Preparation and Characterization of Modified Hydrosol as a SERS-Active Substrate

1998

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The self-assembling technique was employed for modification of a citrate-reduced silver hydrosol with mercaptoethanol (ME). The results of investigation of the structure and properties of both the self-assembled monolayers (SAMs) of ME and the modified hydrosol as a substrate for surface-enhanced Raman scattering (SERS) spectroscopy are presented. ME chemisorbs on the hydrosol by rupture of the S−H bond with concomitant bonding of the sulfur headgroup to Ag. Chemisorption is accompanied by gauche−trans isomerization of ME. The isomerization occurs cooperatively at submonolayer coverage due to interactions of neighboring adsorbed molecules rather than due to the chemisorption itself. The chemisorption of ME takes place on a less than 5 min time scale and leads to formation of a SAM with definite density and gauche−trans equilibrium, the parameters of which depend on the bulk concentration of ME but not on the time of incubation. It was revealed that densely packed and highly ordered (97% of trans-isomers) SAM is formed at an ME concentration higher than 250 μM. ME induces concentration-dependent aggregation of the hydrosol and makes it SERS active. After 30 min of incubation with 250 μM ME the modified hydrosol has the highest Raman enhancement only slightly altered during the next 40−50 min. Preactivation of the hydrosol surface with ClO4 -, NO3 -, Cl-, Br-, and I- anions does not improve SAM formation or Raman enhancement. Using β-carotene as a probe molecule it was well demonstrated that the structured surface of the modified hydrosol provides favorable conditions for increasing the number of adsorption sites and increasing the adsorption constant for an analyte. It also protects an analyte from direct contact with the metal surface, thereby preventing distortion of the electronic system of adsorbed molecule. These advantages make the modified hydrosol a useful tool for SERS probing of chromophores with intense electronic transitions in the visible region.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Surface-Enhanced Raman Scattering (SERS) Study of Mercaptoethanol Monolayer Assemblies on Silver Citrate Hydrosol. Preparation and Characterization of Modified Hydrosol as a SERS-Active Substrate

1998

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“…Recently, we have developed a new approach to the study of CESD based on surface-enhanced Raman scattering (SERS) spectroscopy. , It has been demonstrated that these photochromic ionophores can be traced by the SERS technique in the 10 -5 −10 -8 M range of concentrations not achievable with other spectroscopic (UV−vis, fluorescence, NMR) techniques. By combination of Langmuir−Blodgett and SERS techniques, the extreme sensitivity of the method was utilized in the course of the study of structural organization and aggregation properties of a monolayer of amphiphilic CESD. , The vibrational spectra of the dyes bring a wealth of information regarding the state and interaction of functionally important molecular groups.…”

Section: Introductionmentioning

confidence: 99%

Complexation of Photochromic Crown Ether Styryl Dyes with Mg²⁺ As Probed by Surface-Enhanced Raman Scattering Spectroscopy

et al. 1997

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Complexation with magnesium cations of 2,3,5,6,8,9,11,12-octahydro-1,4,7,10,13-benzopentaoxacyclopentadecin (1), as well as derivatives of crown ether styryl dyes perchlorate 2-[2-(2,3,5,6,8,9,11,12-octahydro-1,4,7,10,13-benzopentaoxacyclopentadecin-16-yl)ethenyl]-3-ethylbenzothiazolium (2), betaine 2-[2-(2,3,5,6,8,9,11,12-octahydro-1,4,7,10,13-benzopentaoxacyclopentadecin-16-yl)ethenyl]-3-(3-sulfopropyl)benzothiazolium (3), betaine 2-[2-(2,3,5,6,8,9,11,12-octahydro-1,4,7,10,13-benzopentaoxacyclopentadecin-16-yl)ethenyl]-3-(3-sulfoethyl)benzothiazolium (4) was studied by surface-enhanced Raman scattering (SERS) spectroscopy. Comparative studies of isomerization and complexation of photochromic ionophores 2−4 with Mg2+ in solution and when adsorbed on the silver surface were performed. The aim was to characterize parameters of these processes depending on the nature (alkyl versus sulfo-alkyl) as well as the length (sulfoethyl versus sulfopropyl) of the N substituent in the benzothiazolium residue. The data obtained indicate stabilization of the trans conformation and prevention of the trans−cis isomerization for the adsorbed molecules as well as for their complexes with Mg2+ due to fast nonradiative energy transfer from the dye excited state to metal surface. Adsorption of a dye having initially cis conformation in solution is accompanied by surface-induced cis−trans relaxation. Adsorption constants calculated from the Langmuir isotherms revealed slightly preferential adsorption of 2−4 complexed with Mg2+ as compared to the free dyes. Desorption of the dyes was found to occur on the hours time scale, whereas reversible capture/release of metal ions by adsorbed molecules is quite fast and may serve as an indicator of a cation level and/or complexation processes in bulk solution. The SERS titration procedure was developed permitting the complexation of the ionophores with metal cations to be followed and equilibrium constants of these processes to be measured in a wide range (down to 10-7 M) of ligand concentrations. By the measurement of the equilibrium constants, adsorption on the silver surface was concluded not to affect the complexation of 1 and trans -2 with Mg2+. Association of the Mg2+ cation with the sulfonate group was found to be more favorable than binding with the crown ether moiety for the adsorbed (trans -3)Mg2+ and (trans -4)Mg2+ complexes. Appearance of the (trans-3)(Mg2+)2 and (trans-4)(Mg2+)2 species was detected in the solution at increased metal/ligand molar ratios. These complexes were found to be unperturbed if absorbed on the silver surface. Since the measurement of equilibrium constants are intractable by other techniques, measuring equilibrium constants for (trans-3)(Mg2+)2 and (trans-4)(Mg2+)2 complexe formation is readily acquired by SERS spectroscopy.

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“…Note that more than 40 nanogaps (<10 nm) between nanoislands on top exist within 1 μm 2 and more than 800 nanogaps (<10 nm) between top nanoislands generate hot spots within a beam spot radius of 2.5 μm (Figure 3b). The SERS signal from the substrate with 30 nm thick silver film shows approximately 16 times higher than that from the two‐dimensional nanoislands produced by silver film annealing (Figure 2a, Figure 3c), even though the two‐dimensional silver nanoislands are considerably an efficient SERS substrate with multiple nanogaps 24, 25. Based on the calculation, the average SERS EF is approximately increased by 2.7 times and the silver surface area by 5.9 times due to the unique feature of silver nanoislands on glass nanopillars.…”

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Electrospray tandem mass spectrometry of underivatised acetylated xylo‐oligosaccharides

Reis

Pinto

Evtuguin

et al. 2005

Rapid Comm Mass Spectrometry

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Acetylated neutral (Xyl(n)Ac(m)) and acidic xylo-oligosaccharides (Xyl(n)Ac(m)MeGlcA, and Xyl(n)Ac(m)MeGlcAHex) obtained by partial acid hydrolysis of Eucalyptus globulus wood glucuronoxylans and fractionated by preparative ligand exchange/size-exclusion chromatography were identified by electrospray ionisation mass spectrometry (ESI-MS). Low molecular weight acetylated xylo-oligosaccharides were studied by ESI-tandem mass spectrometry (MS/MS). All the acetylated xylo-oligosaccharides showed an abundant ion due to the neutral loss of 60 Da (CH(3)CO(2)H) in the MS/MS spectra. The presence of diacetylated xylo-oligosaccharides was confirmed by the ions formed by loss of two molecules of acetic acid. Furthermore, characteristic [Xyl(res)Ac(2)+Na](+) and [XylAc(2)+Na](+) ions, and ions due to loss of XylAc(2), indicate that both acetyl groups are located in the same Xyl residue. On the other hand, losses of Xyl(res)Ac and XylAc are also observed as well as [Xyl(res)Ac+Na](+) and [XylAc+Na](+) , indicating the location of both acetyl groups in different Xyl residues, in some cases even in adjacent xyloses. The MS/MS spectra of triacetylated xylo-oligosaccharides were complex due to the presence of different isobaric xylo-oligosaccharides containing the acetyl groups at different locations in the xylo-oligosaccharide backbone. In the MS/MS spectra of acidic xylo-oligosaccharides, the ion at m/z 387, [Xyl(res)AcMeGlcA+Na](+), indicates that the acetyl groups are preferentially linked to Xyl substituted with MeGlcA. However, acidic xylo-oligosaccharides with the acetyl and 4-O-methylglucuronic acid groups in different Xyl residues were also identified. In neutral and in acidic xylo-oligosaccharides several possible locations of the acetyl groups were identified, namely at terminal positions. In summary, ESI-MS/MS is shown to be a powerful tool for the characterisation of acetylated patterns in complex mixtures of oligosaccharides.

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Annealing of Glass-Deposited Silver Island Films Lead to Creation of Regular Sers-Active Surfaces. Comparative Scanning Tunnel Microscopy and Sers Study

Cited by 3 publications

References 1 publication

Surface-Enhanced Raman Scattering (SERS) Study of Mercaptoethanol Monolayer Assemblies on Silver Citrate Hydrosol. Preparation and Characterization of Modified Hydrosol as a SERS-Active Substrate

Surface-Enhanced Raman Scattering (SERS) Study of Mercaptoethanol Monolayer Assemblies on Silver Citrate Hydrosol. Preparation and Characterization of Modified Hydrosol as a SERS-Active Substrate

Complexation of Photochromic Crown Ether Styryl Dyes with Mg²⁺ As Probed by Surface-Enhanced Raman Scattering Spectroscopy

Electrospray tandem mass spectrometry of underivatised acetylated xylo‐oligosaccharides

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Annealing of Glass-Deposited Silver Island Films Lead to Creation of Regular Sers-Active Surfaces. Comparative Scanning Tunnel Microscopy and Sers Study

Cited by 3 publications

References 1 publication

Surface-Enhanced Raman Scattering (SERS) Study of Mercaptoethanol Monolayer Assemblies on Silver Citrate Hydrosol. Preparation and Characterization of Modified Hydrosol as a SERS-Active Substrate

Surface-Enhanced Raman Scattering (SERS) Study of Mercaptoethanol Monolayer Assemblies on Silver Citrate Hydrosol. Preparation and Characterization of Modified Hydrosol as a SERS-Active Substrate

Complexation of Photochromic Crown Ether Styryl Dyes with Mg2+ As Probed by Surface-Enhanced Raman Scattering Spectroscopy

Electrospray tandem mass spectrometry of underivatised acetylated xylo‐oligosaccharides

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Complexation of Photochromic Crown Ether Styryl Dyes with Mg²⁺ As Probed by Surface-Enhanced Raman Scattering Spectroscopy