排序方式: 共有22条查询结果,搜索用时 15 毫秒
1.
Fabio Gosetti Ugo Chiuminatto Davide Zampieri Eleonora Mazzucco Emilio Marengo Maria Carla Gennaro 《Journal of chromatography. A》2010,1217(20):3427-3434
The study investigates the natural photodegradation pathway of mono-chloroanilines in river waters, with the aim to identify the predominant photoproducts formed. At this purpose a new sensitive on-line SPE HPLC–MS/MS method has been developed with LOQ values equal or lower than the legal threshold concentration levels allowed for mono-chloroanilines in waters. The degradation processes of o-, m- and p-chloroaniline have been investigated subjecting their solutions, prepared both in ultrapure and in river water, to sun light irradiation simulated by a solar box system. The SPE HPLC–MS/MS methodology allowed to evaluate the degradation kinetics, to identify the predominant photodegradation products and to propose the chemical structures. Two photoproducts (aniline and 3-aminophenol), for which standards are available, have also been quantified. 相似文献
2.
Bottaro M Frascarolo P Gosetti F Mazzucco E Gianotti V Polati S Pollici E Piacentini L Pavese G Gennaro MC 《Journal of the American Society for Mass Spectrometry》2008,19(8):1221-1229
The paper studies, with the help of HPLC-DAD-MS/MS technique, the hydrolytic and photoinduced degradation processes that take place in aqueous solutions of tribenuron methyl, both when preserved in the dark and when undergoing solar box irradiation under conditions that simulate sun light. The results indicate that the degradation products formed by hydrolysis alone and by photoirradiation are the same, but kinetics of the hydrolysis reaction is much slower. The degradation products are identified as 2-methoxy-4-methylamino-6-methyl-1,3,5-triazine (P1), methyl 2-aminosulfonylbenzoate (P2), and saccharin (P3) and quantified. Ecotoxicological biotests performed on 0.1 microg L(-1) photoirradiated solutions of the herbicide give a border line toxicity situation comparable to that of the precursor and indicate that the herbicide is characterized by low persistence in the environment, as required. Its degradation, however, does not lead to mineralization but to the formation of products of comparable toxicity. To evaluate the matrix effects, the photodegradation of the herbicide is also studied in the presence of rice paddy waters: the process is slower than in ultrapure water but leads to the same products. Experiments performed for comparison by irradiating ultrapure water solutions with UV lamp (254 nm) show that the degradation process is not only faster with respect to sunlight, but gives a different pathway, without in anyway leading to mineralization. 相似文献
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Fabio Gosetti Eleonora Mazzucco Maria Carla Gennaro Emilio Marengo 《Analytical and bioanalytical chemistry》2013,405(2-3):907-916
The broad group of biogenic amines includes polyamines and catecholamines, whose presence in human tissues and biological fluids can give important diagnostic information and act as marker of many pathologies. In particular, polyamines are involved in cancer cell growth while catecholamines act as neurotransmitters and hormones. Their simultaneous determination in biological tissues and fluids is therefore an important task. A high-performance liquid chromatography tandem mass spectrometry method is presented here for the simultaneous determination in urine of 16 biogenic amines: adrenaline (epinephrine), agmatine, cadaverine, dopamine, histamine, 3-methoxytyramine, noradrenaline (norepinephrine), norephedrine, octopamine, 2-phenylethylamine, putrescine, serotonin, spermidine, spermine, tryptamine, and tyramine. The method does not require any derivatization step. To guarantee the maximum of sensitivity, the mass spectrometer works in selected reaction monitoring mode, monitoring for each analyte the two most intensive transitions. Method validation includes the evaluation of limits of detection (that range from 0.3 to 6.6 μg L?1), limits of quantitation (that range from 1.0 to 21.9 μg L?1), linearity range (three orders of magnitude), recovery, intra- and inter-day precision on both concentration, and retention time. Recovery (R) is shown not to depend on the analyte concentration: the average R percent ranges from 72.9 to 100.0 %. Particular attention is devoted to the matrix effect and the correlated phenomena of ion enhancement or suppression in mass spectrometry detection. Figure
HPLC-MS/MS determination of 16 biogenic amines 相似文献
5.
G. Ajroldi G. Pezzin G. Astarita F. R. Schwarzl L. G. Napolitano E. Butta G. Marrucci U. Bianchi J. C. Halpin L. Nicolais M. Pegoraro E. Pedemonte P. L. Mazzucco L. Patron S. Eccher A. Seves A. Croce G. Manfré A. T. Di Benedetto R. Greco D. Acierno C. Rossi A. Perico G. P. Giuliani W. Conti E. Sorta C. Garbuglio L. Costantino G. Nardi V. Vitagliano L. Nicodemo L. Szilagyi A. C. Bassi U. Delle Piane F. de Candia G. Ballini S. Danesi A. Moroni A. Casale L. Corbelli 《Rheologica Acta》1972,11(1):133-142
6.
Fabio Gosetti Ugo Chiuminatto Eleonora Mazzucco Giorgio Calabrese Maria Carla Gennaro Emilio Marengo 《Analytica chimica acta》2012
The study deals with the identification of the degradation products formed by simulated sunlight photoirradiation in a beverage that contains Allura Red AC (E129) dye. An UHPLC–MS/MS method that makes use of high resolution quadrupole-time-of-flight mass spectrometer, was developed. For the identification of the degradation products the software tool Information Dependent Acquisition (IDA) was used to automatically obtain information about the high resolution MS and MS/MS spectra of the species present. 相似文献
7.
Julien Berger Suelen Gasparin Denys Dutykh Nathan Mendes 《Transport in Porous Media》2018,121(3):665-702
Comparisons of experimental observation of heat and moisture transfer through porous building materials with numerical results have been presented in numerous studies reported in the literature. However, some discrepancies have been observed, highlighting underestimation of sorption process and overestimation of desorption process. Some studies intend to explain the discrepancies by analyzing the importance of hysteresis effects as well as carrying out sensitivity analyses on the input parameters as convective transfer coefficients. This article intends to investigate the accuracy and efficiency of the coupled solution by adding advective transfer of both heat and moisture in the physical model. In addition, the efficient Scharfetter and Gummel numerical scheme is proposed to solve the system of advection–diffusion equations, which has the advantages of being well-balanced and asymptotically preserving. Moreover, the scheme is particularly efficient in terms of accuracy and reduction of computational time when using large spatial discretization parameters. Several linear and nonlinear cases are studied to validate the method and highlight its specific features. At the end, an experimental benchmark from the literature is considered. The numerical results are compared to the experimental data for a pure diffusive model and also for the proposed model. The latter presents better agreement with the experimental data. The influence of the hysteresis effects on the moisture capacity is also studied, by adding a third differential equation. 相似文献
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Danieli Galvan Fábio Carneiro Mateus Mazzucco Julio Roberto Bartoli Marcos Akira d'Ávila Ana Rita Morales Elizabeth Grillo Fernandes 《Macromolecular Symposia》2012,319(1):167-172
Summary: In this work, poly(acrylonitrile-butadiene-styrene) (ABS) and different organically modified montmorillonite clay nanocomposites were prepared by melt intercalation in a co-rotating twin screw extruder. The influence of the screw torque during processing and of the mixture of the modified organoclays in the intercalation/exfoliation of the clay in the polymeric matrix was evaluated through low angle X-ray diffraction range and capillary and parallel plate-plate rheometry. 相似文献
10.
Robotti E Gosetti F Mazzucco E Zampieri D Marengo E 《Journal of the American Society for Mass Spectrometry》2011,22(1):118-129
Standard automatic tuning for mass spectrometry usually exploits a one-variable-at-a-time approach. This method suffers from
important drawbacks: the target function selected for optimization improves the signal of a single channel or a pool of channels
without considering noise; the interactions between the parameters are not evaluated. The optimization of the experimental
settings of an ESI IT mass spectrometer is carried out here by a multivariate procedure exploiting a target function representing
the S/N ratio calculated by principal component analysis and a regular simplex optimization algorithm. A preliminary feasibility
study was performed since the target function must be sensitive to the changes in the experimental conditions applied during
the iterative tuning and be free from drifts. The feasibility study was carried out to evaluate: the presence of memory effects;
the size of the variations in the S/N ratio; the number of scans needed to generate a reliable S/N ratio; the concentration
of the multi-standard mixture to use during tuning; the experimental duration required to achieve S/N stability when the experimental
settings are modified. The feasibility study led to the identification of the best protocol to accomplish the tuning, while
simplex optimization allowed the S/N ratio to be improved by about 70% with respect to the default conditions suggested by
the manufacturer. 相似文献