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Glyphosate is the most widely used herbicide in the world and, in view of its toxicity, there is a quest for easy-to-use, but reliable methods to detect it in water. To address this issue, we realized a simple, rapid, and highly sensitive immunosensor based on gold coated magnetic nanoparticles (MNPs@Au) to detect glyphosate in tap water. Not only the gold shell provided a sensitive optical transduction of the biological signal – through the shift of the local surface plasmon resonance (LSPR) entailed by the nanoparticle aggregation –, but it also allowed us to use an effective photochemical immobilization technique to tether oriented antibodies straight on the nanoparticles surface. While such a feature led to aggregates in which the nanoparticles were at close proximity each other, the magnetic properties of the core offered us an efficient tool to steer the nanoparticles by a rotating magnetic field. As a result, the nanoparticle aggregation in presence of the target could take place at higher rate (enhanced diffusion) with significant improvement in sensitivity. As a matter of fact, the combination of plasmonic and magnetic properties within the same nanoparticles allowed us to realize a colorimetric biosensor with a limit of detection (LOD) of 20 ng∙L−1.

A Laccase-based biosensor for the determination of phenolic compounds was developed by using Matrix Assisted Pulsed Laser Evaporation as an innovative enzyme immobilization technique. and the deriving biosensor was characterized and applied for the first time. Laccase was immobilized onto different substrates including screen printed carbon electrodes and spectroscopic, morphologic and electrochemical characterizations were carried out. A linear range from 1 to 60 μM was achieved working at 5.5 pH and −0.2 V detection potential vs Ag pseudoreference. The limits of detection and quantification were found to be 1 and 5 μM, respectively. A good fabrication reproducibility, stability of response and selectivity toward interferents were also found The potential of the developed biosensor was tested in the determination of total polyphenol content in real matrices (tea infusion, ethanolic extract from Muscari comosum bulbs and aqueous solution of a food supplement from black radish root and artichoke leaves) and the results were compared with those obtained by using the Folin–Ciocalteu method.

In our laboratories we are interested to new superconducting oxides grown by Pulsed Laser Ablation. The SmBaCuO is a new material which has high critical transition temperature and very good critical current. We begin to study the optical spectroscopic data produced by laser interaction with a target and we characterize the structure and the morphology of thin films obtained using x-ray diffraction spectra and Scanning Electron Microscope analysis.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

An investigation on “in situ” laser induced deposition of superconductor Bi 2 Sr 2 CaCu 2 O x (BSCCO) and YBa 2 Cu 3 O x (YBCO) material is here reported. The laser irradiation of the solid sample was performed by a frequency doubled Nd-YAG laser. The thin films deposited on SrTiO 3 substrate were annealed in a high temperature oven. Resistance measurements showed the presence of superconductive transition above 80 K for BSCCO. XPS analysis of “as deposited” and annealed films appears to indicate that in the annealed sample the oxygen and copper valence are restored. Laser ionization mass analysis studies, performed on BSCCO sample showed the presence of cluster ions.

White marble samples from ancient quarries have been analyzed by Laser Induced Breakdown Spectroscopy (LIBS) both on the bulk material and surface encrustations. With the aim to achieve quantitative results by LIBS, until now not reported on marble materials, calibration standards with CaCO3 matrices doped with certified soils were realized. Very different emission intensities and plasma parameters were observed on the standards and natural marbles. In order to compare so different spectra, a method for data analysis was developed, which takes into account variability of the ablation rate, plasma temperature and electron density. It was experimentally demonstrated that ablated volume is well correlated to the emission intensity of plasma continuum for a wide range of laser energies. LIBS signal normalization on the adjacent continuum level, together with introduction of correction factors dependent on plasma parameters, allowed the measuring of concentrations both for major and trace elements in marbles. The analytical procedure was validated by comparative SEM-EDX and ICP-OES measurements. Quantitative LIBS analyses were also performed during encrustation removal and could be applied to control laser-cleaning processes. The quantification of metal contents in the encrustations supported the occurrence of sulfates in the outer layers exposed to environmental agents via a catalytic process.