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排序方式: 共有90条查询结果,搜索用时 31 毫秒
21.
Maria Nieddu Gianpiero Boatto Maria Antonietta Pirisi Elena Baralla 《Rapid communications in mass spectrometry : RCM》2009,23(19):3051-3056
An analytical procedure for the simultaneous determination in human urine of several thioamphetamine designer drugs (2C‐T and ALEPH series) is reported. The quantitative analysis was performed by liquid chromatography/tandem mass spectrometry and has been fully validated. The mass spectrometer was operated in positive‐ion, selected reaction monitoring (SRM) mode. In order to minimize interferences with matrix components and to preconcentrate target analytes, solid‐phase extraction was introduced in the method as a clean‐up step. The entire method was validated for selectivity, linearity, precision and accuracy. The method turned out to be specific, sensitive, and reliable for the analysis of amphetamine derivatives in urine samples. The calibration curves were linear over the concentration range of 1 to 100 ng mL?1 for all drugs with correlation coefficients that exceeded 0.996. The lower limits of detection (LODs) and quantification (LOQs) ranged from 1.2 to 4.9 ng mL?1 and from 3.2 to 9.6 ng mL?1, respectively. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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Federico Cozzi Italo Pellegrini Gianpiero Adami Edoardo Reisenhofer Massimo Bovenzi Pierluigi Barbieri 《Central European Journal of Chemistry》2009,7(3):395-401
Sulphur K-edge X-ray absorption near edge structure (XANES) spectroscopy was used to identify sulphur compounds in PM10 samples
collected simultaneously at two sites with different environmental situations in the province of Trieste (NE of Italy), during
summer and winter seasons respectively. The first site is an industrial site located near a steel mill plant and the second
is a coastal site. The sulphur speciation at the industrial site has shown the presence of the following sulphur compounds
in both seasons: organic compounds (thiophenes or Polycyclic Aromatic Sulphur Heterocycles — PAHs) and sulphates while in
the winter season sulphites were also present. In the coastal site organic compounds (thiophenes or PASHs) and sulphate were
found during winter season, moreover bisulphates were found during summer season. Relative percentages of the different sulphur
compounds have shown that sulphate is the most abundant form of sulphur in the industrial site samples during both seasons
and in the coastal site sample collected during the winter season (> 98%); in the coastal site sample collected during the
summer season the relative percentages of bisulphate and sulphate were around 40% and 60% respectively.
相似文献
25.
Adami G Capriglia L Barbieri P Cozzi F Lo Coco F Acquavita A Reisenhofer E 《Annali di chimica》2006,96(9-10):601-612
The following metals: Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn were determined by inductively coupled plasma - atomic emission spectroscopy (ICP-AES) in fluvial sediments of Rosandra Creek, using two different, strong and mild sediment decomposition methods. The purpose was to obtain information about the contamination by metals and distribution paths of pollutants in the area crossed by Rosandra Creek: this little river is the unique epigeous watercourse in the Italian Karst and very few data can be found in literature. In this area, we can find a natural park, but also agricultural activities and an industrial district that was recently defined as "polluted site of national interest". By comparing the results of the strong and mild extraction we have obtained the percentage of extraction and enrichment factors for each metal in the different sediments of the sites R2 and R3 exposed to pollution, while the site R1 was considered as a pristine one because situated in the natural park. The computed enrichment factors are generally not very high, but copper, lead and zinc have factors that require attention. The principal component analysis (PCA) shows that the typically anthropogenic metals (as Cr, Pb, Cu and Zn) constitute the first factor, while the lithogenic metals, as Fe and Ni, constitute the second one; moreover the score plots permit to classify and distinguish the 3 sites: site R3, possibly the more exposed to contamination, has high scores both for anthropogenic and lithogenic metals. 相似文献
26.
Maria Nieddu Gianpiero Boatto Maria Antonietta Pirisi Giuseppina Dessì 《Rapid communications in mass spectrometry : RCM》2010,24(16):2357-2362
An analytical procedure for the simultaneous determination in human urine of four thiophenethylamine designer drugs (2C‐T series) is reported. The quantitative analysis was performed by capillary electrophoresis with mass spectrometric detection (CE/MS), using 2,5‐dimethoxy‐4‐methylthiophenethylamine‐D4 (2C‐T‐D4) as internal standard. In order to minimize interferences with matrix components and to preconcentrate target analytes, solid‐phase extraction (SPE) was introduced in the method as a clean‐up step. The method was validated according to international guidelines. The data for accuracy and precision were within required limits. Calibration curves were generated over the range from 10 to 500 ng mL?1 and correlation coefficients always exceeded 0.997. The method was demonstrated to be specific, sensitive, and reliable for the analysis of these derivatives in urine samples. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
27.
This article presents and compares various algebraic structures that arise in axiomatic unsharp quantum physics. We begin by stating some basic principles that such an algebraic structure should encompass. Following G. Mackey and G. Ludwig, we first consider a minimal state-effect-probability (minimal SEFP) structure. In order to include partial operations of sum and difference, an additional axiom is postulated and a SEFP structure is obtained. It is then shown that a SEFP structure is equivalent to an effect algebra with an order determining set of states. We also consider -SEFP structures and show that these structures distinguish Hilbert space from incomplete inner product spaces. Various types of sharpness are discussed and under what conditions a Brouwer complementation can be defined to obtain a BZ-poset is investigated. In this case it is shown that every effect has a best lower and upper sharp approximation and that the set of all Brouwer sharp effects form an orthoalgebra. 相似文献
28.
On the basis of Mackey's axiomatic approach to quantum physics or, equivalently, of a state-event-probability (SEVP) structure, using a quite standard fuzzification procedure, a set of unsharp events (or effects) is constructed and the corresponding state-effect-probability (SEFP) structure is introduced. The introduction of some suitable axioms gives rise to a partially ordered structure of quantum Brouwer-Zadeh (BZ) poset; i.e., a poset endowed with two nonusual orthocomplementation mappings, a fuzzy-like orthocomplementation, and an intuitionistic-like orthocomplementation, whose set of sharp elements is an orthomodular complete lattice. As customary, by these orthocomplementations the two modal-like necessity and possibility operators are introduced, and it is shown that Ludwig's and Jauch-Piron's approaches to quantum physics are interpreted in complete SEFP. As a marginal result, a standard procedure to construct a lot of unsharp realizations starting from any sharp realization of a fixed observable is given, and the relationship among sharp and corresponding unsharp realizations is studied. 相似文献
29.
Giorgio Della Sala Angelo Fontana Aldo Spinella Gianpiero Calabrese Giuliana d'Ippolito Guido Cimino 《Tetrahedron》2007,63(30):7256-7263
Secondary metabolites of the Mediterranean mollusc Scaphander lignarius from different collection sites have been investigated, proving the constant presence of a number of minor metabolites correlated to the already known lignarenones. Complete characterization of the new metabolites has been supported by enantioselective synthesis. The data are consistent with the origin of this unique class of ω-phenyloctanoids from a common polyketide pathway. 相似文献
30.
Gianpiero Cattaneo 《Journal of Mathematical Analysis and Applications》1980,75(2):523-548
Classical information systems are introduced in the framework of measure and integration theory. The measurable characteristic functions are identified with the exact events while the fuzzy events are the real measurable functions whose range is contained in the unit interval. Two orthogonality relations are introduced on fuzzy events, the first linked to the fuzzy logic and the second to the fuzzy structure of partial a Baer1-ring. The fuzzy logic is then compared with the “empirical” fuzzy logic induced by the classical information system. In this context, quantum logics could be considered as those empirical fuzzy logics in which it is not possible to have preparation procedures which provide physical systems whose “microstate” is always exactly defined. 相似文献