Functionalization of Ag Nanoparticles with Dithiocarbamate Calix[4]arene As an Effective Supramolecular Host for the Surface-Enhanced Raman Scattering Detection of Polycyclic Aromatic Hydrocarbons (original) (raw)
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Journal of Physical Chemistry B, 2004
Trace concentrations of polycyclic aromatic hydrocarbons (PAHs) have been successfully detected using surface-enhanced Raman scattering (SERS) spectroscopy. For such purpose, new SERS substrates have been developed, consisting of Ag nanoparticles, either in suspension or immobilized on glass, obtained by a new method and covered by adsorbed self-assembled calix[4]arene molecules. Among the assayed calix[4]arenes, the 25,27-dicarboethoxy-26,28-dihydroxy-p-tert-butylcalix[4]arene host molecule displays analytical selectivity to the PAH guest systems bearing four benzene rings, mainly pyrene. The host-guest interaction mechanism seems to take place through a π-π stacking interaction leading to a charge transfer between the complex and the metallic surface, which may also induce a notable influence on the surface charge of the metallic nanoparticle.
Physical Chemistry Chemical Physics, 2009
The absorption and self-assembly of a dithiocarbamate calix[4]arene derivative (DTCX) on Ag nanoparticles (NPs) was characterized in this work by surface-enhanced Raman scattering (SERS). This study was carried out on Ag NPs prepared by chemical reduction of silver nitrate with two different reducing agents: sodium citrate or hydroxylamine hydrochloride. SERS was able to discriminate between the different conformations and interaction geometries adopted by DTCX when adsorbed and self-assembled on Ag NPs at different surface coverings. The identification of structural marker bands was crucial in this study. Furthermore, the structure adopted by DTCX is important to determine the activity of this calixarene as a molecular host to detect pollutants, such as pyrene (PYR), since an excessively open or closed cavity is not efficient regarding the analyte detection.
ACS Applied Nano Materials, 2018
The modification of transition metal dichalcogenides (TMDs), incorporating nitrogen doping and silver nanoparticles (Ag NPs) decoration on the skeleton of exfoliated MoS and WS 2 was accomplished. The preparation of N-doped and Ag NPs decorated TMDs involved an one-pot treatment procedure in a vacuum sputtering chamber under nitrogen plasma conditions and in the presence of a silver cathode as the source. Two different deposition times, 5 and 10 s, respectively, were applied to obtain N-doped with Ag NPs decorated MoS 2 and WS 2 hybrids, abbreviated as N5-MoS 2 /Ag NPs , N10-MoS 2 /Ag NPs , N5-WS 2 /Ag NPs and N10-WS 2 /Ag NPs , respectively, for each functionalization time. The successful incorporation of nitrogen as dopant within the lattice of exfoliated MoS 2 and WS 2 as well as the deposition of Ag NPs on their surface, yielding N-MoS 2 /Ag NPs and N-WS 2 /Ag NPs , was manifested through extensive X-ray photoelectron spectroscopy measurements. The observation of peaks at ~398 eV derived from covalently bonded nitrogen and the evolution of a doublet of peaks at ~370 eV guaranteed the presence of Ag NPs in the modified TMDs. Also, the morphology of N-MoS 2 /Ag NPs and N-WS 2 /Ag NPs was examined by transmission electron microscopy, which proved that silver deposition resulted in nanoparticles growth, rather than creation of a continuous metal film on the TMD sheets. Next, the newly developed hybrid materials were attested as efficient surface enhanced Raman scattering (SERS) platforms by achieving the detection of Rhodamine B (RhB). Markedly, N10-MoS 2 /Ag NPs showed the highest sensitivity for detecting RhB at concentration as low as 10-9 M. Charge-transfer interactions between RhB and the modified
Feasibility of SERS-Active Porous Ag Substrates for the Effective Detection of Pyrene in Water
Sensors
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants that are typically released into the environment during the incomplete combustion of fossil fuels. Due to their relevant carcinogenicity, mutagenicity, and teratogenicity, it is urgent to develop sensitive and cost-effective strategies for monitoring them, especially in aqueous environments. Surface-enhanced Raman spectroscopy (SERS) can potentially be used as a reliable approach for this purpose, as it constitutes a valid alternative to traditional techniques, such as liquid and gas chromatography. Nevertheless, the development of an SERS-based platform for detection PAHs has so far been hindered by the poor adsorption of PAHs onto silver- and gold-based SERS-active substrates. To overcome this limitation, several research efforts have been directed towards the development of functionalized SERS substrates for the improvement of PAH adsorption. However, these strategies suffer from the interference that functionalizi...
Analytica Chimica Acta, 2008
Viologen Lucigenin Molecular recognition Surface-enhanced Raman scattering Nanosensors Organochlorine pesticides a b s t r a c t Organochlorine pesticide endosulfan has been detected for the first time by using surfaceenhanced Raman scattering (SERS) at trace concentrations. The bis-acridinium dication lucigenine was successfully used as a molecular assembler in the functionalization of metal nanoparticles to facilitate the approach of the pesticide to the metal surface. From the SERS spectra valuable information about the interaction mechanism between the pesticide and lucigenin can be deduced. In fact, endosulfan undergoes an isomerization upon adsorption onto the metal, while the viologen undergoes a rotation of the acridinium planes to better accommodate the pesticide molecule. An interaction between the N atom of the central acridinium ring and the pesticide Cl-C C-Cl fragment is verified through a charge-transfer complex. The present study affords important information which can be applied to the design of chemical sensor systems of persistent organic pollutants based on the optical detection on functionalized metal nanoparticle.
SERS is a thirty years old physical phenomenon that has become one of the most exciting analytical techniques with a wide range of applications in physics, chemistry and biology, and the corresponding applied sciences. This ultrasensitive analytical tool covers the complete scale of sensitive analysis and diagnostics down to the limit of single molecule detection (SMD). There are now thousands of SERS publications in a wide range of scientifi c journals (for instance, SERS papers can be found in all the journals published by the ACS). The applications are relevant to trace analysis, environmental monitoring, nanobioscience among many others. The fi eld is intrinsically connected with the optical properties of nanostructures and SERS techniques are also used for nanostructure characterization, since it can be discussed in terms of surface plasmon resonance of nanoparticles, nanoshells or voids, leading to nanophotonics, plasmonics and single-molecule detection. Therefore, nowadays, no attempt or claim can be made to review the fi eld exhaustively in its entirety nor to cover all applications. Some of the above invited speakers contributed to the present issue. The speakers and the audience were able to exchange their views and newly acquired results in lively and sometimes heated discussions. The poster session was also quite active and successful. A total of 49 posters were displayed during the symposium. The following presentations received the Poster Awards. H. K. Park et al. "Silver-Particle-Based Surface-Enhanced Raman Scattering Spectroscopy for Biomolecular Sensing and Recognition" M. Meyer et al. "Can the Orientation of Molecules be Measured with SERS?" A. Maio et al. "SERRS measurement and Structural Characterization of J-and H-Aggregates in Langmuir-Blodgett (LB) Films Containing Merocyanine Dye"
Optics and Photonics Journal, 2013
While Raman spectroscopy is a useful method for analyzing many organic compounds, it is limited by relatively low sensitivity. Therefore, Surface Enhanced Raman Spectroscopy (SERS) based on the adsorption of organic analytes onto gold or silver nanostructures has been used to enhance the signal of chemicals presented at very low concentrations. Although the plasmonic effect of SERS has been shown to play a large role in signal enhancement, the significance of the chemical effect due to the analyte chemisorption on the gold or silver surface is less well understood. In this study, the role of aniline substituents is examined by probing the SERS intensities of various anilines in silver and gold colloids using a Raman spectrometer with an excitation wavelength of 785 nm. The SERS enhancement factors and detection limits for aniline and its mono-and di-substituted ortho derivatives are determined and compared. Both the steric requirements of chemisorption and the inductive effects of electron-withdrawal due to the substituents affect the signal intensities of various vibrational modes of the amino group and the aromatic ring. The degree of enhancement is also related to the methods for preparing the silver and gold colloids, which are characterized by probing the nanoparticle morphology and its degree of aggregation using transmission electron microscopy (TEM).
Vibrational Spectroscopy, 2008
A humic acid (HA) extracted from lignite was successfully used in surface-enhanced Raman scattering SERS experiments as molecular occlusion assembler deposited onto a Ag colloidal surface to detect the polycyclic aromatic hydrocarbons PAHs chrysene and pyrene. Thus, this is the first time that HA compounds are employed in the design of metal nanoparticles-based sensors for pollutants detection. Chrysene (Chr) and pyrene (Pyr) were detected at low concentration. A charge transfer between HA and the analyte characterizes their interaction. The interaction resulted to be more significant in the case of the pyrene molecule. Extended Hückel calculations based on a molecular model for the interacting PAHs/HA/Ag system support the experimental conclusions. The PAHs-HA distance is about 3.5 Å and the most probable orientation for both analytes is plane parallel to the aromatic fragments of HA. An energy transfer, from the silver surface to HA and from the analyte to HA, is concluded.