Search results for "010401 analytical chemistry"
showing 10 items of 1284 documents
The identification of autoionizing states of atomic chromium for the resonance ionization laser ion source of the ISOLDE radioactive ion beam facility
2017
Abstract This paper presents the results of an investigation into autoionizing states of atomic chromium, in the service of the resonance ionization laser ion source (RILIS): the principal ion source of the ISOLDE radioactive ion beam facility based at CERN. The multi-step resonance photo-ionization process enables element selective ionization which, in combination with mass separation, allows isotope specific selectivity in the production of radioactive ion beams at ISOLDE. The element selective nature of the process requires a multi-step “ionization scheme” to be developed for each element. Using the method of in-source resonance ionization spectroscopy, an optimal three-step, three-reson…
Assessment of the influence of counter ions on biosorption of copper cations in brewer's spent grain - Waste product generated during beer brewing pr…
2019
Abstract The influence that conditioning leached ground barley grain (known as “brewer's spent grain” (BSG)) has on the effectiveness of copper cation sorption was analysed. Saturation with counter ions of functional groups present on the grain surface was carried out in hydrochloric acid, sodium hydroxide, sodium and calcium chloride solutions. For comparison, BSG was also conditioned in demineralised water. Spent barley grain is a by-product of the brewing industry which can be used as a biosorbent in the removal of heavy metals from waste water. Emphasis is placed on the effect of competitive sorption of copper and hydrogen cations and the negative influence of a solution alkalinisation …
Dispersive magnetic immunoaffinity extraction. Anatoxin-a determination.
2017
Specific monoclonal antibodies were coupled with magnetic Sepharose-based beads and used, for the first time. The methodology was applied to preconcentrate anatoxin-a from water and the later determination by ion mobility spectrometry (IMS). Dispersive magnetic immunoaffinity (d-MagIA) extraction methodology provided a limit of detection of 0.02μgL-1 and a satisfactory precision with a relative standard deviation lower than 15%. Recoveries were evaluated at 0.5, 1.0 and 5.0μgL-1 anatoxin-a with quantitative values from 91 to 115%. Additionally, isobaric interferences with phenylalanine were completely avoided by the use of the developed d-MagIA extraction coupled to IMS determinations.
Collision induced fragmentations of multiply charged sodium bis(2-ethylhexyl)-sulfosuccinate aggregates in gas phase: neutral loss versus charge sepa…
2016
Abstract Stability and fragmentation patterns of multicharged aggregates of sodium bis(2-ethylhexyl)-sulfosuccinate (NaAOT) in gas phase have been investigated by ion mobility mass spectrometry (IM-MS) and tandem mass spectrometry (MS-MS). Positively doubly charged NaAOT aggregates show at low collision energy a preference for the loss of NaAOT molecules, whereas fragmentation through charge separation process is favored at higher collision energy. By increasing the charge state of the aggregates, the fragmentation through charge separation tends to predominate especially at low aggregation number and only charge separation fragmentation is observed for positively quadruply charged species.…
Fast and direct analysis of oxidation levels of oil-in-water emulsions using ATR-FTIR.
2019
International audience; Oxidation of omega-3 fatty acids is a major limitation on its enrichment in food and beverages. An efficient and simple method to monitor lipid oxidation in complex systems is essential to limit lipid oxidation during formulation and processing. Fish oil-in-water emulsions (20% v/v) were exposed to iron or free radical initiated oxidation. Conjugated dienes (CDs) were rapidly measured using a previously developed fat extraction method. Fourier transform infrared (FTIR) spectroscopy has been used to directly record chemical changes occurring during oxidation. Variations were noticed in different spectral regions despite the presence of broad water bands near 3400 and …
Effect of sodium dodecyl sulphate and Brij-35 on the analysis of sulphonamides in physiological samples using direct injection and acetonitrile gradi…
2016
Micellar liquid chromatography (MLC) is a reversed-phase (RP) mode, which often does not require gradient elution, since the peaks of mixtures of compounds within a large range of polarities appear more evenly distributed in the chromatograms of isocratic elution, giving rise to a “gradient effect”. However, the use of a gradient of organic solvent may still be convenient to shorten the total analysis time. This work compares the separation of 15 sulphonamides using conventional hydro-organic RPLC and MLC with the surfactants sodium dodecyl sulphate (SDS) and Brij-35, and both isocratic and gradient elution with acetonitrile. The observed behaviour is rationalized attending to the interacti…
Evaluation of furanocoumarins from seeds of the wild parsnip (Pastinaca sativa L. s.l.).
2018
Abstract Although the wild parsnip (Pastinaca sativa L. s.l.) fruits are known to contain linear and angular furanocoumarins, the individual components of the seeds have not been fully identified and quantitated, and, in the case of immature seeds, reported. In view of this, the main furanocoumarin compounds were extracted using pyridine, and were isolated using semi-preparative high-performance liquid chromatography. The structural elucidation of isolated compounds was done based on detailed spectral analysis conducted by liquid chromatography–electrospray ionization–mass spectrometry (LC–ESI/MS), 1H and 13C NMR and, where possible, by gas chromatography–mass spectrometry (GC–MS). The quan…
Application of Resonance Ionization Mass Spectrometry for Ultratrace Analysis of Technetium
2017
This work shows the ability of resonance ionization mass spectrometry (RIMS) to determine 99gTc at the ultratrace level. The characterization of the prepared samples by X-ray photoelectron spectroscopy (XPS) and optimization of the RIMS setup for this purpose, as well as the application of the RIMS method to a soil sample, are presented in this article. 97Tc was used as a tracer isotope to determine the amount of 99gTc in a soil sample with RIMS. With 8.8 × 1010 atoms of 97Tc as the tracer, the concentration of 99gTc was found to be 1.5 × 109 atoms per gram of dried sample material, demonstrating the sensitivity of the method. Furthermore, it could be shown that the 97Tc solution contained …
Triple Isotope Fractionation Exponents of Elements Measured by MC-ICP-MS—An Example of Mg
2019
In most chemical reactions, stable isotopes are fractionated in a mass-dependent manner, yielding correlated isotope ratios in elements with three or more stable isotopes. The proportionality between isotope ratios is set by the triple isotope fractionation exponent θ that can be determined precisely for, e.g., sulfur and oxygen by IRMS, but not for metal(loid) elements due to the lower precision of MC-ICP-MS analysis and smaller isotopic variations. Here, using Mg as a test case, we compute a complete metrologically robust uncertainty budget for apparent θ values and, with reference to this, present a new measurement approach that reduces uncertainty on θ values by 30%. T…
Zircon M127 - A Homogeneous Reference Material for SIMS U-Pb Geochronology Combined with Hafnium, Oxygen and, Potentially, Lithium Isotope Analysis
2016
Faculty of Geosciences, Geography and Astronomy, University of Vienna; Beijing SHRIMP Centre, Chinese Academy of Geological Sciences; European Commission [MEXC-CT-2005-024878]; FWF Austrian Science Fund [P20028-N10, P24448-N19]; U.S. National Science Foundation [EAR 1524336]