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91.
92.
The configurational isomers of astaxanthin (3,3′-dihydroxy-β,β-carotene-4,4′-dione) from the flesh of salmon (Salmo salar and Oncorhynchus) caught at different places in Europe and Canada were isolated and analyzed as (?)-camphanic acid diesters by means of HPLC. The biological variation in the composition of the configurational isomers in seven fish was surprisingly similar: 78 to 85% of (3S, 3′S)-astaxanthin, 12 to 17% (3R, 3′R)-astaxanthin and 2 to 6% meso-astaxanthin. 相似文献
93.
Katharina Schiedt Max Vecchi Ernst Glinz Trond Storebakken 《Helvetica chimica acta》1988,71(4):887-896
Diets supplemented with astaxanthin and canthaxanthin, respectively, and a control diet without carotenoid additions, were fed to 1½-year-old Atlantic salmon (Salmo salar, L.) for one year. The integuments were investigated as to their quantitative and qualitative carotenoid composition. Astaxanthin and canthaxanthin deposited in the skin amounted to 20 and 14% of the total carotenoids only. Seventy % must be considered as metabolites of astaxanthin and canthaxanthin and 10% as basic xanthophylls also present in the control groups. Astaxanthin apparently underwent the following metabolic pathway: astaxanthin→idoxanthin→adonixanthin→zeaxanthin→zeaxanthin 5,6-epoxides. Reduction of the 4′-carbonyl group was stereospecific leading to the (4′R)-idoxanthin. Canthaxanthin was obviously converted to β,β-carotene via 4′-hydroxyechinenone, echinenone, and 4-hydroxy-β,β-carotene. 相似文献
94.
95.
Max H. Feinberg Christian J. Ducauze 《Fresenius' Journal of Analytical Chemistry》1991,339(9):604-607
Summary Chemometrics have been described as effective tools for exploring chemical data, and many software packages are now available on micro-computers. This work evaluate their suitability for environmental analytical chemistry. Guidelines for multivariate method selection are proposed. They are based on the type of variables and the goal of the study. Two examples are proposed to illustrate these methods and their efficiency. Firstly it is shown that a global assessment of Rhine basin mercuric pollution in the Alsace region is possible with Multiple Correspondence Factor Analysis. Several goals are simultaneously reached: a mapping of pollution, a detection of pollution changes during the study period and an evaluation of bio-accumulation as a function of fish species. Secondly the modeling of industrial soil pollution by heavy metals is studied by Multiple Linear Regression. It demonstrates that chemometrics provide us with necessary tools for environmental analytical chemistry but also for toxicological studies or ecosystem modeling. 相似文献
96.
Karlheinz Ballschmiter Rainer Bacher Angela Mennel Regina Fischer Ulrich Riehle Max Swerev 《Journal of separation science》1992,15(4):260-270
High resolution gas chromatography, with mass selective detection, has been used for the analysis of PCB on methyl 50 % octyl polysiloxane (SB 50 Octyl), methyl octadecyl polysiloxane, and a smectic polysiloxane (SB Smectic); and for the analysis of polychlorodibenzodioxins and polychlorodibenzofurans with 1 to 8 chlorine substituents on 100 % cyanopropyl siloxane (SP 2331), smectic polysiloxane (SB Smectic), a new polar stationary phase (DB-Dioxin). The analysis has also been performed by column coupling. 相似文献
97.
Burlakov VV Arndt P Baumann W Spannenberg A Rosenthal U Parameswaran P Jemmis ED 《Chemical communications (Cambridge, England)》2004,(18):2074-2075
The 2,5-dititanabicyclo[2.2.0]hex-1(4)-ene (bis-titanocene-mu-(Z)-1,2,3-butatriene complex)3 is formed starting from [Cp2Ti(eta2-Me3SiC2SiMe3)] by in situ generated titanocene and 1,4-dichlorobut-2-yne via the 1-titanacyclobut-3-yne (2). 相似文献
98.
Ursula Baumann 《Fresenius' Journal of Analytical Chemistry》1963,193(6):456
Ohne Zusammenfassung
Folin, O.: Hoppe-Seylers Z. physiol. Chem. 41, 223 (1904); vgl. diese Z. 44, 459 (1905). 相似文献
99.
J.Georges Duboudin Michel Petraud Max Ratier Bruno Trouve 《Journal of organometallic chemistry》1985,288(1):C6-C8
Flash pyrolysis of alkyltributyltin acetates, at high temperatures (600–850° C) under a moderate vacuum provides a convenient route to vinyltin derivatives. 相似文献
100.
Lalith Perera Max L. Berkowitz 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1993,26(1):166-168
We describe here molecular dynamics computer simulations performed to study the solvation of ions (Cl? and Na+) in water clusters. Our simulations show that the calculated structure and dynamics of the clusters is very sensitive to the potential model which is used to describe the interactions. From the comparison with thermodynamic data and data from the photoelectron spectra we conclude that in Cl?(H2O)n (n≤20) clusters the ion is located on the surface of the cluster. 相似文献