Search results for "Silver"
showing 10 items of 697 documents
Le suppellettili liturgiche dagli anni Ottanta del Settecento ai primi decenni dell’Ottocento
2016
Il saggio analizza le suppellettili liturgiche d'argento delle chiese di Petralia Soprana realizzate dagli anni Ottanta del Settecento ai primi decenni dell’Ottocento per aggiornare e ampliare il patrimonio d'arte sacra del centro madonita. La lettura dei marchi e il ritrovamento di inediti documenti d'archivio hanno consentito di riferire le opere ad alcuni maestri palermitani, come Salvatore La Cecla e Salvatore Mercurio, e di individuare in qualche caso anche i committenti. The essay analyzes the silver liturgical furnishings of the churches of Petralia Soprana built from the eighties of the eighteenth century to the first decades of the nineteenth century to update and expand the herita…
Optical recognition and removal of Hg(II) using a new self-chemosensor based on a modified amino-functionalized Al-MOF
2017
Abstract We developed a simple self-chemical optical sensor for the monitoring and removal of ultra-trace levels of Hg(II) from aqueous media. The development of this sensor was based on the covalent attachment of amino-functionalized aluminum-based MOF particles with ninhydrin. The new sensor is densely coated with a chelating ligand to permit an ultra-fast, selective, pH-dependent visualization for removal of Hg(II) with detection limit (LOD∼0.494 μg L−1). Monitoring was accomplished via both a colorimetric signal visible to the naked eye as well as UV–vis absorption spectroscopy. Digital image-based colorimetric analysis has also used as a semi-quantitative analysis for determination the…
Silver based sensors from CD for chloride ions detection
2021
This preliminary work shows a new and innovative way to produce silver based electrodes from compact discs and its application towards the detection of chloride ions. A complete sensor was obtained from the compact discs with working, reference and counter electrode made of silver. Chloride ions were detected by exploiting the high affinity of silver with this anion to produce silver chloride. This electrochemical oxidation of silver can be monitored by using an electrochemical technique such as linear scan voltammetry. Indeed, during linear scan voltammetry the oxidation of silver to silver chloride lead to a peak current that increases linearly with chloride concentration. Using this tech…
Flow spectrophotometric determination of ammonium ion
1999
Abstract A flow procedure is proposed for the determination of ammonium ion. The sample in basic medium is forced through a solid-phase reactor containing immobilized AgCl on polymeric pearl beads. The released Ag + , complexed with the ammonia, gives a blue ternary complex with the aid of bromopyrogallol red and 1,10-phenanthroline which is spectrophotometrically monitored at 636 nm. The calibration graph is linear over the range 1–20 μg ml −1 ammonium ion, detection limit ( s / n = 3) 0.35 μg ml −1 and relative standard deviation (slope) 1.9 % ( n = 7). The sample throughput is 48 h −1 . The influence of foreign compounds is studied and the procedure is applied to ammonium ion determi…
Use of thermal ionization isotope dilution mass spectrometry (TI-IDMS) as an oligo-element method for the determination of photographically relevant …
1998
Thermal ionization isotope dilution mass spectrometry (TI-IDMS) was used as an oligo-element method for the determination of Cr, Cd and Pb in photographic AgCl emulsions. After addition of an appropriate amount of isotopically enriched spikes (53Cr, 116Cd and 206Pb) to the solid samples, the latter were completely dissolved in NH3 solution, permitting isotopic exchange to take place. Thereafter, AgCl was selectively removed by precipitation, whereby ultrasonic treatment was used to enhance the recovery of the elements of interest. Despite the use of concentrated HNO3 and H2O2 during further sample processing, preliminary experiments indicated the presence of a substantial remainder of the o…
Indirect Determination of Cyanide by Atomic Absorption Spectrometry
1995
Abstract Two methods for determination of cyanide by atomic absorption spectrometry (AAS) are developed. Both methods are based on the formation of an ion association compound between a metal complex, (Ag(CN)2 − or Cu(CN)3 2-), and a quaternary ammonium ion (benzyldimethylhexadecylammonium ion). The ion association compound is extracted into isomethylbutylketone (IBMK) and the metal is determined by AAS directly in extract. The method based on the formation of silver cyanide complex provides a reproducibility of 2.5%, a recovery of 99% and a detection limit of 1.7 μg/L while the method based on the formation of copper complex gives a reproducibility of 6%, a recovery of 93% and a detection …
Application of stable isotopes and AF4/ICP-SFMS for simultaneous tracing and quantification of iron oxide nanoparticles in a sediment–slurry matrix
2016
One major challenge in nanomaterial analysis, especially in complex environmental matrices, is the unambiguous differentiation between natural and engineered nanomaterials (ENMs). Particularly with regard to the investigation of ENM's/engineered nanoparticle's (ENPs) fate, analytical methods are needed allowing for tracing and sensitive quantification. Several ENPs are metal-based and contain elements being omnipresent in environmental matrices (e.g., Al, Ti, Zn, Fe and non-metal Si) – hence, high background levels of these elements are expected, compromising sensitive detection. In this work we developed successfully a combined approach of stable isotope labeling (tracing) and reverse post…
Fabrication of silver nanoparticles by a diethylene triamine-hyaluronic acid derivative and use as antibacterial coating
2022
In this work a synthetic protocol for the functionalization of hyaluronic acid with diethylenetriamine (DETA) was standardized. HA-DETA derivatives were characterized by NMR and proton carbon correlation analysis HSQC and HMBC to confirm chemical structure. A selected derivative was used to set up a green fabrication procedure for HA-DETA capped silver nanoparticles with the aim to achieve a polymeric based coating with potential application in the treatment of medical devices associated infections. Data from UV-visible spectroscopy, electron scanning and transmission microscope (STEM), photoelectric spectroscopy (XPS) and rheological characterization were combined to characterize the HA-DE…
Enhanced Surface Ligands Reactivity of Metal Clusters by Bulky Ligands for Controlling Optical and Chiral Properties.
2021
Surface ligands play critical roles in determining the surface properties of metal clusters. However, modulating the properties and controlling the surface structure of clusters through surface‐capping agent displacement remain a challenge. In this work, a silver cluster, [Ag 14 (SPh(CF 3 ) 2 ) 12 (PPh 3 ) 4 (DMF) 4 ] ( Ag 14 ‐DMF , where HSPh(CF 3 ) 2 is 3,5‐bis(trifluoromethyl)benzenethiol, PPh 3 is triphenylphosphine and DMF is N,N‐Dimethylformamide), with weakly coordinated DMF ligands on the surface silver sites, was synthesized by using a mixed ligands strategy (bulky thiolates, phosphines and small solvents). The as‐prepared Ag 14 ‐DMF is a racemic mixture of chiral molecules. Owing …
From the Golgi-Cajal mapping to the transmitter-based characterization of the neuronal networks leading to two modes of brain communication: Wiring a…
2007
After Golgi-Cajal mapped neural circuits, the discovery and mapping of the central monoamine neurons opened up for a new understanding of interneuronal communication by indicating that another form of communication exists. For instance, it was found that dopamine may be released as a prolactin inhibitory factor from the median eminence, indicating an alternative mode of dopamine communication in the brain. Subsequently, the analysis of the locus coeruleus noradrenaline neurons demonstrated a novel type of lower brainstem neuron that monosynaptically and globally innervated the entire CNS. Furthermore, the ascending raphe serotonin neuron systems were found to globally innervate the forebrai…