Search results for "fume"

A chromatochemometric approach for evaluating and selecting the perfume maceration time.

2010

Abstract A chemometric treatment of the data obtained by gas chromatography (GC) with flame ionization detector (FID) has been proposed to study the maceration time involved in perfumes manufacture with the final purpose of reducing this time but preserving the organoleptic characteristics of the perfume that is being elaborated. In this sense, GC–FID chromatograms were used as a fingerprint of perfume samples subjected to different maceration times, and data were treated by linear discriminant analysis (LDA), by comparing to a set of samples known to be macerated or not, which were used as calibration objects. The GC–FID methodology combined with the treatment of data by LDA has been appli…

Il fumetto può aiutare nei processi di insegnamento/apprendimento delle Matematiche?

2010

Analytical Methods for the Determination of Perfume-related Substances.

2014

Las fragancias son productos químicos que desprenden un olor agradable y que se utilizan en multitud de productos de consumo a los que confieren su característico aroma. Así, se pueden encontrar en productos cosméticos de todo tipo (tales como perfumes, champús, desodorantes o jabones) y también en productos para el hogar (como detergentes, ambientadores o velas). El uso de productos cosméticos se ha incrementado progresivamente con el paso del tiempo, considerándose un indicador del progreso y bienestar de un país. El reciente Reglamento Europeo sobre productos cosméticos armoniza íntegramente las normas comunitarias a fin de lograr la libre circulación de los productos y garantizar un ele…

Determination of Selected Phthalates by Gas Chromatography–Mass Spectrometry in Personal Perfumes

2015

A simple and fast method is proposed to analyze commercial personal perfumes. Our method includes measurement of phthalates, known to be major sources of endocrine disruptor chemicals (EDC), which originate from the less volatile fraction of perfumes. The quantification of phthalates were carried out directly with no sample preparation required on 30 samples of commercial products using gas chromatography and mass spectrometry (GC-MS) as a detector. The total concentrations of 15 investigated compounds ranged from 17 to 9650 mg/L with an average of 2643 mg/L. The highest total concentration was found in cologne. Diethyl phthalate (DEP), diisobutyl phthalate (DiBP), di(2-ethylhexyl) phthalat…

Properties of HO2• radicals induced by γ-ray irradiation in silica nanoparticles

2014

Abstract We report an experimental investigation on the effects of γ -ray irradiation in several types of silica nanoparticles previously loaded with O 2 molecules. They differ in specific surface and average diameter. By electron paramagnetic resonance (EPR) measurements we observe the generation of about 10 18 HO 2 • /cm 3 interstitial radicals. These radicals are induced by reaction of interstitial O 2 molecules with radiolytic H atoms, as previously suggested for O 2 -loaded bulk a-SiO 2 samples. However, at variance with respect to bulk materials, our experimental evidences suggest a different generation process of HO 2 • radical. In fact, by a detailed study of samples exposed to D 2 …

Investigation on the ganaration process of HO2• radicals by γ-ray irradiation in O2-loaded fumed silica

2013

Abstract We report an experimental investigation on the effects of γ-ray irradiation in three types of fumed silica previously loaded with O 2 molecules. Our data indicate that the main effect of irradiation in these systems is to generate a very large concentration of HO 2 interstitial radicals (about 10 18  molecules/cm 3 ). Furthermore, the number of generated HO 2 was found to be larger in the samples with higher O 2 contents before irradiation. This correlation suggests that HO 2 radicals are induced by reaction of interstitial O 2 molecules with radiolytic H atoms, as previously suggested for O 2 -loaded bulk amorphous silicon dioxide (a-SiO 2 or silica) samples. However, at variance …

Low-cost materials for boron adsorption from water

2012

[EN] Knowing the affinity of boron aqueous species for cis-diol organic groups, five different hybrid materials have been prepared by anchoring glucose groups onto the surface of silica matrices with a different surface topology: UVM-7 bimodal mesoporous silica, UVM-11 unimodal non-templated mesoporous silica, commercial silica fume and two silica xerogels with pores within the mesoporous range (13-50 nm). After optimizing the experimental conditions, a comparison was made of the boron adsorption capacities in water. The relationship of the structural and functionalization parameters is discussed and the importance of the surface topology in the final adsorption behaviour is revealed. Hence…

Physico-chemical evolution of low-pH cements : influence of the temperature and the retention mechanisme of alkalins

2010

Because of their high alkalinity, Portland cement (OPC)-based materials may have deleterious effects in an underground waste repository. A solution would be to use low-alkalinity cements (also referred as low-pH cements) generating interstitial solutions with a reduced pH (11 instead of 13.5 for OPC), and thus showing an improved chemical compatibility with the repository environment. In this work, the investigated formulations were based on binary (OPC / silica fume) or ternary (OPC / silica fume / slag or fly ash) blends, with high substitution levels of CEM I (from 30% to 80%). This research project met two main objectives: (i) study the chemical evolution of low-pH cements at 50°C or 80…

Acute hepatotoxicity of the polycyclic musk 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphtaline (AHTN).

2000

Synthetic musks are present in fine fragrances, cosmetics, soaps and laundry detergents. One of the most important synthetic musks is 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydro-naphthaline+ ++ (AHTN; annual production: about 1500 metric tons). An increasing number of studies show that AHTN accumulates in surface water and fish and can be detected in human adipose tissue, as well in human milk. In the present report it is shown that a single high dose of AHTN leads to acute hepatic damage in rats, characterized by single cell necrosis, inflammation, swelling of liver parenchymal cells, and the presence of cytoplasmic condensations in the hepatocytes, while at the ultrastructural leve…

Sintering process of amorphous SiO2 nanoparticles investigated by AFM, IR and Raman techniques

2011

We report an experimental investigation on the effects of thermal treatments at different temperatures (room-1270 K) and for different duration (0-75 h) on amorphous silica nanoparticles (fumed silica) in powder tablet form. Three types of fumed silica are considered, comprising nearly spherical particles of 40 nm, 14 nm and 7 nm mean diameter. The experimental techniques used here are Raman and infrared absorption (IR) spectroscopy together with atomic force microscopy (AFM). Raman and IR spectra indicate that the structure of nanometer silica particles is significantly different with respect to that of a bulk silica glass. In particular, the main differences regard the positions of the IR…