37 research outputs found
Targeted multidimensional gas chromatography using a heart-cutting device and cryogenic focusing for the determination of benzophenone derivatives in foodstuffs
Photoinitiators are used to promote the polymerization process during the curing of varnishes or inks on cartonboard packaging. Depending on storage conditions and shelf life, these substances are able to migrate through the packaging layer into the foodstuff. This type of contamination phenomenon is therefore becoming a critical issue in terms of food safety. In order to tackle this problem, a fast and selective method was developed for the determination of benzophenone and three methylbenzophenone isomers in cereal-based foodstuffs and their cardboard packaging. Food samples or packages were efficiently extracted by pressurized liquid extraction using acetonitrile, and the extracts were directly injected onto the analytical system. The analysis was performed by multidimensional gas chromatography-mass spectrometry using a heart-cutting approach to reduce the background noise from complex matrices. The strategy employed two distinct cuts each containing its proper deuterated internal standard leading to accurate quantification. By integrating a cryofocusing effect, an enhancement in signal/noise ratio was achieved by a factor >10, which markedly decreased the sensitivity threshold. Moreover, baseline separation of the critical isomers allowed their unequivocal determination. The method was fully validated on cereal-based foodstuffs based upon an analysis of variance, and excellent performances were obtained at the decision limit making this method well suited for official food control
A complete solution to neutrino mixing
Deviations from expectations have been claimed for solar, atmospheric and
high energy prompt neutrinos from charm decay. This information, supplemented
only by the existing very good upper limits for oscillations of the
at accelerator energies, is used as input to a phenomenological three-flavour
analysis of neutrino mixing. The solution found is unique and completely
determines the mass eigenstates as well as the mixing matrix relating mass and
flavour eigenstates. Assuming the mass eigenstates to follow the hierarchy
, their values are found to be
eV, eV, eV. These masses are
in agreement with the leptonic quadratic hierarchy of the see-saw model and
large enough to render energy-independent any oscillation-induced phenomenon in
solar neutrino physics observable on Earth. This possibility is not excluded by
the present knowledge of solar neutrino physics. The mixing angles are
determined to be , ,
. Small values of are typical of any solution
in which lies in the cosmological interesting region. The solution
found is not in serious contradiction with any of the present limits to the
existence of neutrino oscillations. The most relevant implications in particle
physics, astrophysics and cosmology are discussed.Comment: 17 pages, 3 figures, to be published in Astroparticle Physic
E-cigarette liquids: Constancy of content across batches and accuracy of labeling
To assess whether bottles of refill liquids for e-cigarettes were filled true to label, whether their content was constant across two production batches, and whether they contained impurities
A fast LC-APCI/MS method for analyzing benzodiazepines in whole blood using monolithic support
Targeted multidimensional gas chromatography using a heart-cutting device and cryogenic focusing for the determination of benzophenone derivatives in foodstuffs
Photoinitiators are used to promote the polymerization process during the curing of varnishes or inks on cartonboard packaging. Depending on storage conditions and shelf life, these substances are able to migrate through the packaging layer into the foodstuff. This type of contamination phenomenon is therefore becoming a critical issue in terms of food safety. In order to tackle this problem, a fast and selective method was developed for the determination of benzophenone and three methylbenzophenone isomers in cereal-based foodstuffs and their cardboard packaging. Food samples or packages were efficiently extracted by pressurized liquid extraction using acetonitrile, and the extracts were directly injected onto the analytical system. The analysis was performed by multidimensional gas chromatography–mass spectrometry using a heart-cutting approach to reduce the background noise from complex matrices. The strategy employed two distinct cuts each containing its proper deuterated internal standard leading to accurate quantification. By integrating a cryofocusing effect, an enhancement in signal/noise ratio was achieved by a factor >10, which markedly decreased the sensitivity threshold. Moreover, baseline separation of the critical isomers allowed their unequivocal determination. The method was fully validated on cereal-based foodstuffs based upon an analysis of variance, and excellent performances were obtained at the decision limit making this method well suited for official food controls
Le Bugey
août 19291929/08 (T7,FASC23).Note : 02 PI 0000 vues Réd. 00 x.Appartient à l’ensemble documentaire : RhoneAlp1Appartient à l’ensemble documentaire : RfnEns0Appartient à l’ensemble documentaire : RfnEuro1Appartient à l’ensemble documentaire : RfnCoop
Contact dermatitis caused by homemade "slime": Report of two cases with chemical analysis
Targeted Screening and Quantification of dl-PCBs and Dioxins in Various Foodstuffs by Programmed-temperature Vaporizer Large-volume Injection Coupled to GC–MS
In 2009, high concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs) were found in soils located near the municipal garbage incinerator of Geneva. The matter of food contamination
in this area was raised. Based on exposure criteria, a strategy of analysis of animal fats has been established with farmers in the Geneva area. Most methods of analysis of dl-PCBs, dioxins and furans, are based on gas chromatography coupled to high-resolution mass spectrometry (GC-HRMS) and
considered as the reference methodology. An innovative approach was developed by programmed-temperature vaporizer large-volume injection (PTV-LV) and gas chromatography coupled with triple quadrupole mass spectrometry (GC-MS/MS) analysis. This analytical method was validated and was found
suitable for screening and quantification of target compounds in animal fats (beef, pork, sheep, etc. ). PTV-LV coupled to GC-MS/MS appeared to be a good alternative compared to the GC-HRMS strategy, offering a good compromise between sensitivity, versatility of instrumentation, and economical aspects. A survey of 121 samples was conducted