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31.
Libuse Trnkova Ladislav Novotny Nuria Serrano Katerina Klosova Petra Polaskova 《Electroanalysis》2010,22(16):1873-1880
Elimination voltammetry with linear scan (EVLS) in connection with renewed mini‐ drop mercury electrodes provides valuable information about the character and kinetics of processes at electrode/electrolyte interfaces. Based on the experiment related to the hydrogen evolution, it is presented that the EVLS is more sensitive than other voltammetric methods. Using miniaturized mercury electrodes, the EVLS is capable of detecting the effect of spherical diffusion associated with both the scan rates and the size of an electrode drop. 相似文献
32.
Direct chemical profiling of olive (Olea europaea) fruit epicuticular waxes by direct electrospray‐ultrahigh resolution mass spectrometry
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Stefania Vichi Nuria Cortés‐Francisco Agustí Romero Josep Caixach 《Journal of mass spectrometry : JMS》2015,50(3):558-566
In the present paper, an electrospray ionization (ESI)‐Orbitrap method is proposed for the direct chemical profiling of epicuticular wax (EW) from Olea europaea fruit. It constitutes a rapid and efficient tool suitable for a wide‐ranging screening of a large number of samples. In a few minutes, the method provides a comprehensive characterization of total EW extracts, based on the molecular formula of their components. Accurate mass measurements are obtained by ultrahigh resolution mass spectrometry, and compositional restrictions are set on the basis of the information available from previous studies of olive EW. By alternating positive and negative ESI modes within the same analysis, complementary results are obtained and a wide range of chemical species is covered. This provides a detailed compositional overview that otherwise would only be available by applying multiple analytical techniques. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
33.
Luis Fermín Capitán-Vallvey Nuria López-Ruiz Antonio Martínez-Olmos Miguel M. Erenas Alberto J. Palma 《Analytica chimica acta》2015
Chemical analysis based on colour changes recorded with imaging devices is gaining increasing interest. This is due to its several significant advantages, such as simplicity of use, and the fact that it is easily combinable with portable and widely distributed imaging devices, resulting in friendly analytical procedures in many areas that demand out-of-lab applications for in situ and real-time monitoring. This tutorial review covers computer vision-based analytical (CVAC) procedures and systems from 2005 to 2015, a period of time when 87.5% of the papers on this topic were published. The background regarding colour spaces and recent analytical system architectures of interest in analytical chemistry is presented in the form of a tutorial. Moreover, issues regarding images, such as the influence of illuminants, and the most relevant techniques for processing and analysing digital images are addressed. Some of the most relevant applications are then detailed, highlighting their main characteristics. Finally, our opinion about future perspectives is discussed. 相似文献
34.
Quantum dot-based array for sensitive detection of <Emphasis Type="Italic">Escherichia coli</Emphasis> 总被引:1,自引:0,他引:1
Sanvicens N Pascual N Fernández-Argüelles MT Adrián J Costa-Fernández JM Sánchez-Baeza F Sanz-Medel A Marco MP 《Analytical and bioanalytical chemistry》2011,399(8):2755-2762
A fluorescent quantum dot-based antibody array, used in sandwich format, has been developed to detect Escherichia coli O157:H7. Numerous parameters such as solid support, optimal concentration of immunoreagents, blocking reagents, and assay
time were optimized for array construction. Quantum dot-conjugated anti-IgG was used as the detecting system. The array allows
the detection of E. coli O157:H7 at concentrations below 10 CFU mL−1 without sample enrichment, exhibiting an increase of three orders of magnitude in the limit of detection compared to ELISA.
The interference caused by Gram (+) and Gram (−) bacteria was negligible at low concentrations of bacteria. 相似文献
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A kinetic study of the decomposition reactions of N-bromoalanine, N-bromo-2-aminobutyric acid, and N-bromonorvaline shows them to be first-order with respect to N-bromoaminoacid concentration and independent of both excess aminoacid and pH over the interval pH 9–11. In this pH range the mean rate constants at 298 K were 1.20 × 10?3 s?1, 1.37 × 10?3 s?1 and 1.28 × 10?3 s?1, respectively. © 1993 John Wiley & Sons, Inc. 相似文献
38.
J. M. Antelo F. Arce J. L. Armesto A. Garcia-Verdugo F. J. Penedo A. Varela 《国际化学动力学杂志》1985,17(11):1231-1245
The kinetics of the chlorination of various tertiary alcoholamines by hypochlorite have been studied in alkaline media. A reaction mechanism consistent with the experimental results is put forward, and a relationship is established between the rate constants and the polar parameter (Σσ*) of the substituents. 相似文献
39.
Néstor Armesto Alexei B. Kaidalov Carlos A. Salgado Konrad Tywoniuk 《The European Physical Journal C - Particles and Fields》2010,68(3-4):447-457
We consider deep inelastic scattering off nuclei in the Regge limit within the Glauber–Gribov model. Using unitarized parton distribution functions for the proton, we find sizeable shadowing effects on the nuclear total and longitudinal structure functions, $F_{2}^{A}$ and $F_{L}^{A}$ , in the low-x limit. Extending a fan-diagram analysis for the large-mass region of coherent diffraction off nuclei to high Q 2, we also find significant shadowing effects in this kinematical regime. Finally, we discuss the shortcomings of our approach and possible extensions of the model to other kinematical regimes. 相似文献
40.
Broniatowski M Vila Romeu N Dynarowicz-Łatka P 《The journal of physical chemistry. B》2006,110(7):3078-3087
This work presents the results of phase behavior studies of two-dimensional (2D) binary systems involving semifluorinated alkanes (SFAs) and fatty alcohols. Four different SFAs were selected for investigations: (i) with a short and branched perfluorinated moiety (iF3H20), (ii) with a short and normal perfluorinated chain (F4H20), (iii) with a long and branched perfluorinated fragment (iF9H20), and (iv) with a long and normal perfluorinated group (F10H20). Two alcohols were selected to mix with the above-mentioned SFAs: tetradecanol and docosanol. The measurements were based on surface pressure/area isotherms in addition to Brewster angle microscope (BAM) imaging. Dependencies of the collapse surface pressure and the compression modulus vs the monolayer composition together with the excess free energy of mixing values, complemented with BAM images, enabled us to draw some general conclusions regarding the phase behavior of the investigated mixed systems. Generally, it has been noticed that the addition of docosanol into an SFA monolayer exerts a condensing effect, contrary to tetradecanol. Moreover, SFAs with a long perfluorinated segment mix to a larger extent with alcohols as compared to their analogues having a short perfluorinated moiety. The resultant phase diagrams for all the investigated eight mixtures are presented and discussed. 相似文献