Search results for " chimica"
showing 10 items of 3438 documents
Formaldehyde and total aldehydes in indoor air of public environments by voltammetry
2014
The proposed method involves active sampling, where a sampling pump is used to pull air through a solution and voltammetric analysis of the obtained solutions. No interferences have been observed. In addition, very little sample preparation is required. Analyses were performed in 19 indoor stations and one in outdoor. Measurements were carried out on University environments: Museum of Chemistry, Zoological Museum, libraries, laboratories, corridors, meeting rooms, photocopying room, machine shop and terrace. Formaldehyde concentrations in analyzed samples ranged from 2.6 to 85 μg m-3 (median = 32 μg m-3), while the sum of others aldehydes ranged from 2 to 25 μg m-3 (median =2.4 μg m-3). In …
Electrochemical sensor for phosphate ions based on laser scriber reduced graphene oxide
2022
This preliminary work shows a new and innovative way to produce laser scribed reduced graphene oxide (LSGO) electrodes using different porous substrates (ranging from paper to plastic and fabric). The obtained electrodes were also tested as electrochemical sensors towards the detection of phosphate ions in water. To obtain the electrodes, a water suspension of GO was filtered on top of substrate (such as Whatman® filter paper) and a complete sensor was obtained from its reduction using a CO2 laser. The electrode is composed of working and counter electrodes made of LSGO and a reference electrode of a Ag/AgCl obtained by using a commercial AgCl conductive paste. Phosphate ions were detected …
Micro-determination of dithiocarbamates in pesticide formulations using voltammetry
2013
Abstract The purpose of this work was to develop a reliable method for the micro-determination of dithiocarbamates (mancozeb, maneb, propineb, nabam, Na(CH3)2DTC, zineb, ziram, ferbam and thiram) in pesticide formulations for agriculture using adsorptive stripping voltammetry (AdSV). The accuracy of analytical method was valued by analyzing simulate formulation samples prepared by us with known amounts of active ingredients. In addition, the applicability of the AdSV procedure for the analysis of DTCs and EBDTCs in micro-samples was evaluated by estimating its recoveries from spiked commercial formulate samples. The accuracy, valuated as recovery percentage ranged between 85% and 97%. The p…
Voltammetric determination of platinum in perfusate and blood: Preliminary data on pharmacokinetic study of arterial infusion with oxaliplatin
2012
Abstract Because Platinum Group Elements have found widespread use in catalytic converters in cars and as chemotherapeutic agent, interest in the development of reliable analytical methods is carried out in order to monitor these analita in humans to protect the citizen's health. Considering that information on the levels of many trace elements in biological matrices is scarce and for many non-essential elements, baseline levels in the population, and especially in those particularly exposed to the risk are lacking, in this paper we optimize an analytical method for biological matrices, using a voltammetric technique to measure the concentration of Pt in blood and perfusate. The amount of P…
Quantification of Platinum in Edible Mushrooms Using Voltammetric Techniques
2021
Edible mushrooms are a food source with interesting nutritional values. The chief objective of this research was to develop a consistent method for the quantitative ultra-trace analysis of Pt in mushrooms, which is complex because it cannot be readily quantified by common analytical procedures. This research is one of the first analytical methods to establish Pt amount in these vegetables. In this research, 28 different edible mushroom samples from Italy were investigated. Determination of Pt in mushrooms was completed using Differential Pulse Voltammetry (DPV). In this study, we applied the standard addition method because there are no certified reference mushrooms containing platinum grou…
Consolidation tests on the graffiti of the Steri’s prison with nanotechnological Ca(OH)2 dispersed in iso-propanol
2009
The combination of weathering and human activities often induce pyhisicochemical alteration on the surface of wall paintings. One of the most still largely used restoration techniques for these works of art, is based on the application of organic polymers. Due to their ability to stick detached and powdered pigments,these products provide an immediate consolidating effects. Unfortunately, both their aging and their pyhisicochemical incompatibility with the inorganic support can have serious consequences also causing further damage to the work of art. In this paper a new technological approach is presented based on the use of Ca(OH)2 nanoparticles dispersed in isopropanol. Some applicative t…
Gli affreschi provenienti dalle terme romane di Reggio Calabria. Dalla conoscenza al restauro
2023
The frescoes at marine thermae discovered in 1886 during the excavation of the small thermal complex dating between the 1th and 3rd century AD, and located on the seafront of Reggio Calabria, have been collected already collapsed. They are currently part of the permanent exhibition of the National Archaeological Museum of Reggio Calabria. This paper illustrates the results of the restoration intervention, carried out in the form of an educational activity in the context of an agreement signed between the MarRC and the University of Calabria, and the results of the diagnostic investigations carried out by the IPCF-CNR of Messina and the STEBICEF department of the University of Palermo.
Electrochemical treatment of real wastewater with low or high conductivity
2018
In the last years, many efforts have been devoted to the development of electrochemical processes for the effective treatment of wastewater contaminated by organic pollutants resistant to conventional biological processes and/or toxic for microorganisms [1–5]. It was shown that some electrochemical approaches, including the direct anodic oxidation at suitable anodes such as boron-doped diamond (BDD) and/or electro-Fenton (EF) at suitable operating conditions and cells [1–6] can allow to treat effectively a very large number of organic pollutants. However, most of the investigations were performed using synthetic wastewater. Hence, it is now mandatory to study the problems connected to the p…
The Effect of Electrolytic Solution Composition on the Structure, Corrosion, and Wear Resistance of PEO Coatings on AZ31 Magnesium Alloy
2020
Plasma electrolytic oxidation coatings were prepared in aluminate, phosphate, and silicate-based electrolytic solutions using a soft-sparking regime in a multi-frequency stepped process to compare the structure, corrosion, and wear characteristics of the obtained coatings on AZ31 magnesium alloy. The XRD results indicated that all coatings consist of MgO and MgF2, while specific products such as Mg2SiO4, MgSiO3, Mg2P2O7, and MgAl2O4 were also present in specimens based on the selected solution. Surface morphology of the obtained coatings was strongly affected by the electrolyte composition. Aluminate-containing coating showed volcano-like, nodular particles and craters distributed over the …
Vertically Aligned Nanowires and Quantum Dots: Promises and Results in Light Energy Harvesting
2023
The synthesis of crystals with a high surface-to-volume ratio is essential for innovative, high-performance electronic devices and sensors. The easiest way to achieve this in integrated devices with electronic circuits is through the synthesis of high-aspect-ratio nanowires aligned vertically to the substrate surface. Such surface structuring is widely employed for the fabrication of photoanodes for solar cells, either combined with semiconducting quantum dots or metal halide perovskites. In this review, we focus on wet chemistry recipes for the growth of vertically aligned nanowires and technologies for their surface functionalization with quantum dots, highlighting the procedures that yie…