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931.
This review covers two important techniques, high resolution nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS), used to characterize food products and detect possible adulteration of wine, fruit juices, and olive oil, all important products of the Mediterranean Basin. Emphasis is placed on the complementary use of SNIF-NMR (site-specific natural isotopic fractionation nuclear magnetic resonance) and IRMS (isotope-ratio mass spectrometry) in association with chemometric methods for detecting the adulteration.  相似文献   
932.
The calculated parameters of the EPR spectra of complexes of d1 and d9 ions were presented. The covalent bond parameters used in the calculations were determined from EPR and experimental optical data (inverse problem of EPR spectroscopy). Various contributions to the expressions for the EPR parameters were compared. The observed abnormal values of the EPR parameters were discussed. The effects of charge-transfer states and the vibronic coupling on the components of g, A, and AL tensors were considered. Mechanisms of spin density transfer to ligands in paramagnetic complexes were proposed.  相似文献   
933.
Main aspects of the activity of the outstanding Ukrainian analyst A.K. Babko are considered.Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 2, 2005, pp. 211–213.Original Russian Text Copyright © 2005 by Shtokalo.This revised version was published online in April 2005 with corrections to the author names and book review format.  相似文献   
934.
Reduction of alkyl-2-amino-5,6-dialkyl-3-cyanopyridine-4-carboxylates with sodium borohydride in protic solvents gave rise to 4-amino-3-imino-6,7-dialkyl-1,3-dihydrofuro[3,4-c]pyridines that at hydrolysis in acid medium afforded the corresponding lactones.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 2, 2005, pp. 288–291.Original Russian Text Copyright © 2005 by Vasil’ev, Lyshchikov, Nasakin, Kayukov, Tafeenko.  相似文献   
935.
3-(2-Benzimidazolyl)-4-hydroxy-2-quinolone was unexpectedly obtained as the principal reaction product on fusion of 2-carbethoxymethyl-4H-3,1-benzoxazin-4-one with o-phenylenediamine. A possible mechanism of its formation is presented.For Communication 2 see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 239–241, February, 1992.  相似文献   
936.
Summary A survey of the authors' work on liquid chromatography of platinum metals in the form of chelates with 1-(2-pyridylazo)-2-naphthol (PAN) is given. Extraction chromatography with PAN in isopentanol as a stationary phase was used to achieve a group concentration of these metals (Pd, Pt and Rh, concentration coefficient 100) from large volumes of aqueous solutions and a selective extraction of palladium from solutions containing other platinum, nonferrous and heavy metals on a 85–98° C thermostatted chromatographic column. The prospects for the use of liquid chromatography in the analysis of platinum metals are discussed.
Flüssig-Chromatographie von Platinmetallen und zukünftige Entwicklungen
  相似文献   
937.
The effects of the nature of the metal atom and -substituents in aluminum(III), chromium(III), cobalt(III), and iron(III) acetylacetonates on the lifetime and intensity of a long-lived component in positron and positronium annihilation were studied by the method of positron diagnostics. An addition of a positron to the -system of a chelate ring is supposed, which makes it possible to qualitatively estimate the basicities of the complexes. Annihilation of positrons and halogen-containing positronium -diketonates is accompanied by the formation of a protonated complex; for -organylthioacetylacetonates, annihilation follows the inhibition mechanism.  相似文献   
938.
Procedures for synthesis of coordination compounds of copper(II) with bis(5-amino-1,2,4-triazol-3-yl)alkanes as ligands. A conclusion was drawn that the coordination polyhedron of copper(II) has different configurations depending on the structure of the ligand and on the coordination mode.  相似文献   
939.
Weak interactions of nonaromatic amino acids with - and -cyclodextrins in aqueous solutions at 298.15 K were studied calorimetrically. The structure and solvation of these compounds noticeably affect the thermodynamic characteristics of interparticle interactions.  相似文献   
940.
Combined methods for the determination of noble metals with the use of sorption preconcentration with complexing, anion-exchange, and other sorbents are reviewed. Characteristics of sorbents, techniques of sorption preconcentration, and techniques for the preparation of a concentrate for determination are considered. Features of instrumental methods for the determination of noble metals in the analysis of different materials are discussed. Examples of the use of sorption preconcentration in combined methods for the determination of noble metals are given from publications between 1996–2005.  相似文献   
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