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31.
Validation of the Tessier scheme for speciation of metals in soil using the Bland and Altman test 总被引:1,自引:0,他引:1
Tiberiu Frentiu Michaela Ponta Erika Levei Emilia Gheorghiu Iosif Kasler Emil A. Cordos 《Chemical Papers》2008,62(1):114-122
The Tessier extraction method was used for speciation of Cu, Pb, Zn, As, Fe and Mn in a large concentration range in contaminated
soil with various mineralogical compositions. The results were compared by X-ray fluorescence spectrometry (XRF) as a reference
method using the Bland and Altman test. A sum of five fractions (exchangeable, bound to carbonates, Fe-Mn oxides, organic
matter and residual forms) was compared with the total content determined on solid matrix by the reference method. A good
agreement between the methods in the whole concentration range was found for Cu, Zn, As, and Fe. For Mn and Pb, XRF was found
suitable to verify the sequential extraction only for concentrations above 250 mg kg−1. This was a consequence of a poorer reproducibility of Pb extraction using the Tessier scheme due to a great difference in
the mineralogical composition and the diversity of the Pb species identified in soil. The poorer result of Mn was attributed
to the spectral interference of Fe in XRF.
Presented at the 34th International Conference of the Slovak Society of Chemical Engineering, Tatranské Matliare, 21–25 May
2007. 相似文献
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András Simon Erika Liktor‐Busa Gábor Tóth Zoltán Kele Judit Groska Mária Báthori 《Helvetica chimica acta》2008,91(9):1640-1645
Three new and one known ecdysteroids were identified in the MeOH extract of the roots of Serratula wolffii. The new compounds isolated were (11α)‐11‐hydroxyshidasterone ( 1 ), (2β,3α,5β,14β,22R)‐2,3,20,22,25‐pentahydroxycholest‐7‐en‐6‐one ( 2 ), and (2β,3α,5β,22R)‐2,3,20,22,25‐pentahydroxycholest‐7‐en‐6‐one ( 3 ), together with the known ponasterone A ( 4 ). This latter compound was now better characterized than earlier. The structures of compounds 1 – 4 were established by extensive spectroscopic techniques, including one‐ and two‐dimensional NMR methods. 相似文献
34.
Michael addition reaction of α-branched aldehydes to β-nitroacrylates was successfully carried out by using a mixed catalyst consisting of a primary amino acid, L-phenylalanine, and its lithium salt to give β-formyl-β'-nitroesters having a quaternary carbon centre in good yields (up to 85%) with high enantioselectivity (up to 98% ee). By using benzyl β-nitroacrylates as Michael acceptors, the obtained β-formyl-β'-nitroesters were converted into various 4,4-disubstituted pyrrolidine-3-carboxylic acids including analogues of gabapentin (Neurotin(?)) in one step from the Michael adducts in high yields. 相似文献
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Zusammenfassung Dusch- und Schaumbadepr?parate sowie Haarwaschmittel enthalten als Hauptbestandteile im allgemeinen anionische und nichtionische,
gelegentlich auch noch amphotere Tenside. In der vorliegenden Arbeit wird ein Analysengang beschrieben, der nicht nur die
Auftrennung der Tensidgemische und die Identifizierung und Bestimmung der eingesetzten Tenside behandelt, sondern auch Methoden
für den Nachweis und die Bestimmung von Hilfs- und Zusatzstoffen angibt. Daneben wird versucht, die Analysenm?glichkeiten
von Verbindungen aufzuzeigen, die den Pr?paraten besondere zus?tzliche Eigenschaften neben der prim?r gewünschten Reinigungswirkung
verleihen. Zur Isolierung dieser Substanzen (wie z.B. der Sterine und Konditioniermittel) sind von uns Methoden erarbeitet
worden, die in dieser Arbeit erstmalig mitgeteilt werden.
On the analysis of body and hair shampoos based on synthetic tensides
Summary In general, body and hair shampoos contain as main components anionic and non-ionic, sometimes also amphoteric, detergents. A scheme of analysis is given here which not only deals with the separation of the detergent mixtures and the identification and determination of the surfactants employed but also with methods for the detection and determination of additive and auxiliary compounds. Moreover, the attempt is made to point out analytical methods for the determination of those compounds which impart special qualities to the bath preparations and shampoos besides the primary wanted cleaning effect. Methods for the isolation of these substances (as e.g. sterols and conditioning agents) have been elaborated and are described in this paper for the first time.
相似文献
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Recent work has elucidated the potential of important new therapeutic paradigms, including metronomic delivery and chronotherapy, in which the precise timing and location of therapeutic administration has a significant impact on efficacy and toxicity. New drug delivery architectures are needed to not only release drug continuously at precise rates, but also synchronize their release with circadian cycles. We present an actively controlled nanofluidic membrane that exploits electrophoresis to control the magnitude, duration, and timing of drug release. The membrane, produced using high precision silicon fabrication techniques, has platinum electrodes integrated at the inlet and outlet that allow both amplification and reversal of analyte delivery with low applied voltage (at or below 2 VDC). Device operation was demonstrated with solutions of both fluorescein isothiocyanate conjugated bovine serum albumin and lysozyme using fluorescence spectroscopy, fluorescence microscopy, and a lysozyme specific bio-assay and has been characterized for long-term molecular release and release reversibility. Through a combination of theoretical and experimental analysis, the relative contributions of electrophoresis and electroosmosis have been investigated. The membrane's clinically relevant electrophoretic release rate at 2 VDC exceeds the passive release by nearly one order of magnitude, demonstrating the potential to realize the therapeutic paradigm goal. 相似文献
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