Search results for "Spectrophotometry"
showing 10 items of 644 documents
Determination of cobalt in foods by atomic absorption and inductively coupled plasma spectrometry (Short communication)
1988
Effects of weathering on the performance of self-cleaning photocatalytic paints
2019
Abstract The use of photocatalytic products for the surface coating of buildings is spreading more and more, because of the reduction of atmospheric pollutants and the colour maintenance of the paints over time with reduction of the maintenance costs and the improvement of the aesthetic appearance. The study reports the evaluation of the effects of the atmospheric conditions on three commercial photocatalytic paints containing TiO2. In particular tests were carried out by using samples subjected to accelerated aging inside a climate chamber and naturally aged by exposure for two years to the external environment of the city of Palermo (representative of a coastal environment of the Mediterr…
Growth of manganese sulfide (α-MnS) thin films by thermal vacuum evaporation: Structural, morphological and optical properties
2016
Abstract MnS thin films have been successfully prepared by thermal evaporation method at different substrate temperatures using different masses of MnS powder. The prepared films were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and UV–visible spectrophotometry. The XRD measurements show that the films crystallized in the pure α-MnS for substrate temperatures above 100 °C. The optical bandgap of thin films is found to be in the range of 3.2–3.3 eV. A factorial experimental design was used for determining the influence of the two experimental parameters on the films growth.
Fast determination of fish mineral profile. Application to Vietnamese panga fish
2013
A methodology, based on inductively coupled plasma optical emission spectrometry after microwave-assisted digestion with HNO3/H2O2, was developed to determine the mineral profile of panga fish samples imported from Vietnam. A total of 42 essential and toxic elements were studied in seven samples taken from the local market. Preliminary studies were focused on selecting the best wavelength and the required dilution of samples in order to provide the highest sensitivity to maximize the number of analytes to be determined without spectral or matrix interferences. Adequate accuracy was assured by the analysis of certified reference material TORT-2. Mercury was also determined by a direct method…
Novel 1H-pyrrolo[2,3-b]pyridine derivative nortopsentin analogues: synthesis and antitumor activity in peritoneal mesothelioma experimental models.
2013
In this study, we describe the synthesis of new nortopsentin analogues, 1H-pyrrolo[2,3-b]pyridine derivatives and their biological effects in experimental models of diffuse malignant peritoneal mesothelioma (DMPM), a rare and rapidly fatal disease, poorly responsive to conventional therapies. The three most active compounds, 1f (3-[2-(5-fluoro-1-methyl-1H-indol-3-yl)-1,3-thiazol-4-yl]-1H-pyrrolo[2,3-b]pyridine), 3f (3-[2-(1H-indol-3-yl)-1,3-thiazol-4-yl]-1-methyl-1H-pyrrolo[2,3-b]pyridine), and 1l (3-[2-(5-fluoro-1-methyl-1H-indol-3-yl)-1,3-thiazol-4-yl]-1-methyl-1H-pyrrolo[2,3-b] pyridine), which were shown to act as cyclin-dependent kinase 1 inhibitors, consistently reduced DMPM cell prol…
Assignment of complex species by affinity capillary electrophoresis: The case of Th(IV)‐desferrioxamine B
2020
International audience; The electrophoretic mobility change of desferrioxamine B (DFO) was monitored by UV absorption spectrophotometry upon increasing the thorium(IV) concentration in the background electrolyte at two acidities ([HClO4]Tot = 0.0316 and 0.0100 M). These data enabled to assess the speciation model and to determine the equilibrium constant of [Th(DFO)H2]3+ at fixed ionic strength (I = 0.1 M (H,Na)ClO4). Affinity capillary electrophoresis (ACE) turned out to be most helpful in identifying the complexed species by ascertaining its charge and protonation state. The assignment of the correct stoichiometry relied on the reliable estimation of the electrophoretic mobility by assumi…
Photophysical properties of a rhodium tetraphenylporphyrin-tin corrole dyad. The first example of a through metal-metal bond energy transfer
2005
The luminescence spectroscopy study and the determination of the photophysical parameters for the M-M'-bonded rhodium meso-tetraphenylporphyrin-tin(2,3,7,13,17,18-hexamethyl-8,12-diethylcorrole) complex, (TPP)Rh-Sn(Me6Et2Cor) 1, was investigated. The emission bands as well as the lifetimes (tau(e)) and the quantum yields (Phi(e); at 77 K using 2MeTHF as solvent) were compared with those of (TPP)RhI 2 (TPP = tetraphenylporphyrin) and (Me6Et2Cor)SnCl 3 (Me6Et2Cor = 2,3,7,13,17,18-hexamethyl-8,12-diethylcorrole) which are the two chemical precursors of 1. The energy diagram has been established from the absorption, fluorescence and phosphorescence spectra. The Rh(TPP) and Sn(Me6Et2Cor) chromop…
Determination of mycotoxins produced by Fusarium isolates from banana fruits by capillary gas chromatography and high-performance liquid chromatograp…
1997
A method of analysis for trichothecenes (nivalenol, deoxynivalenol, 3- and 15-acetyldeoxynivalenol, diacetoxyscirpenol, neosolaniol, T-2 tetraol, T-2 and HT-2 toxins), zearalenone and zearalenols, and another method for determination of fumonisin B1 are described and applied to cultures of Fusarium isolated from bananas. Both methods were adapted from different techniques of extraction, clean-up and determination of these mycotoxins. The first method involves extraction with methanol-1% aqueous sodium chloride, clean-up of extracts by partition with hexane and dichloromethane, additional solid reversed-phase clean-up and analysis of two eluates by both high-performance liquid chromatography…
Stable amorphous calcium carbonate is the main component of the calcium storage structures of the crustacean Orchestia cavimana.
2002
Amorphous calcium carbonate (ACC) is the least stable form of the six known phases of calcium carbonate. It is, however, produced and stabilized by a variety of organisms. In this study we examined calcium storage structures from the terrestrial crustacean Orchestia cavimana, in order to better understand their formation mode and function. By using X-ray diffraction, infrared and Raman spectroscopy, thermal analysis and elemental analysis, we determined that the mineral comprising these storage structures is amorphous calcium carbonate with small amounts of amorphous calcium phosphate (5%). We suggest that the use of amorphous calcium carbonate might be advantageous for these storage struct…
Determination of the mineral composition of foods by infrared spectroscopy: a review of a green alternative.
2014
The determination of mineral composition of foods involves, in most cases, the use of long and tedious sample preparation, which consumes acids and reagents and sometimes requires the use of expensive instrumentation. This is the main reason for the search for direct analytical procedures, based on the use of infrared sample spectra and chemometrics, to model the signals in order to determine the presence of essential and trace toxic elements in foods. The state-of-the-art of the research in this field has been established in the present review article from the critical evaluation of articles available in the literature. Chemometric methods employed and their validation, together with a dis…