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51.
Thin-layer chromatographic behavior of rare earths on silica gel with aqueous alkaline earth metal nitrate solutions as mobile phases 总被引:1,自引:0,他引:1
The TLC behavior of all the rare earths except Pm has been surveyed on silica gel (pH 7.0) pretreated with 0.1 mol L(-1) tris(hydroxymethyl)aminomethane and 0.1 mol L(-1) HCl with aqueous nitrate solutions of alkaline earth metals as mobile phases. The RF values of the lanthanides varied in a regular and characteristic way accompanied by the tetrad effect with increasing atomic number, and when the mobile phases were changed the RF values of each metal decreased in the order Mg2+ > Ca2+ > Sr2+ > Ba2+, as the crystal ionic radii of the alkaline earth metals increased. This adsorption sequence was not observed with alkali metal nitrate and alkali metal chloride mobile phases. A brief discussion concerning the effect on RF values of the solvent cations and the adsorption mechanism is included; also presented are typical chromatograms for the separation of multi-component mixtures containing adjacent lanthanides. 相似文献
52.
A methanol extract from Prunus mume Sieb. Et Zucc. showed a suppressive effect of the SOS-inducing activity on the mutagen 3-amino-1,4-dimethyl-SH-pyrido[4,3-b]indole(Trp-P-1) in the Salmonella typhimurium TA1535/pSK1002 umu test. The methanol extract was re-extracted with hexane, dichloromethane, ethyl acetate, butanol and water. The dichloromethane and ethyl acetate fractions showed suppressive effect. Suppressive compounds were isolated by silica gel column chromatography and identified as trimethyl citrate (1) and dimethyl citrate (2) by GC-MS, IR and 1H and 13C-NMR spectroscopy. Compounds 1 and 2 suppressed 51 and 39% of the SOS-inducing activity at a concentration of 2.0 micromol/mL. 相似文献
53.
Yasuyuki Takeda Chihiro Takagi 《Journal of inclusion phenomena and macrocyclic chemistry》1994,17(1):93-97
The theory is derived to determine the dimer-formation constant,K
2, of a crown ethermetal salt 111 complex in organic solvents of low dielectric constant by solvent extraction. The theoretical predictions are verified experimentally by extraction of sodium picrate (NaA) with 15-crown-5 (15C5) into carbon tetrachloride. All the experiments were conducted at 25°C. The logK
2 value of the Na(15C5)A complex in carbon tetrachloride has been determined to be 4.05±0.11. Moreover, the partition constant of the complex is calculated. 相似文献
54.
Kikuo Takeda Chikashi Akamatsu Yasuhiko Inoue 《Fresenius' Journal of Analytical Chemistry》1991,339(1):50-54
Summary Trace amounts of tin were concentrated by coprecipitation and determined by electrothermal atomisation atomic absorption spectrometry. Yttrium hydroxide coprecipitated quantitatively 0.1–3 g of tin from 50–500 ml of sample solution at pH 9.5–11.2. The atomic absorbance of tin increased about twice by using an impregnated graphite tube with yttrium. The impregnated graphite tube, furthermore, improved the reproducibility of the measurement of tin. A linear calibration graph was obtained in the range of 0.004–0.12 g/ml of tin. Twenty-three foreign ions did not interfere seriously. The method was applicable to the determination of tin in zinc metal. 相似文献
55.
Highly Selective Separation of Rhodopsin from Bovine Rod Outer Segment Membranes Using Combination of Divalent Cation and Alkyl(thio)glucoside 总被引:1,自引:0,他引:1
The micellization process of bovine rod outer segment (ROS) membranes is investigated utilizing a series of neutral detergents. It is found that when alkyl(thio)glucosides with an appropriate hydrophilic–lipophilic balance (e.g. octylthioglucoside) are used in combination with a divalent cation, rhodopsin is selectively extracted from ROS membranes at a specific detergent-to-membrane ratio. This allows remarkable purification of rhodopsin by a single-step solubilization, because the residual membranes are heavily aggregated in the presence of divalent cation and are therefore easily sedimented by low-speed centrifugation. The absorption spectrum of the supernatant reproducibly exhibits an A280 /A500 value of 1.6, an excellent value that could rarely be obtained by chromatographic purification. The degree of purification also depends on the type of divalent cation included in the solubilization solution; specific binding of IIB-series cations (Zn2+ and Cd2+ ) to ROS membranes is suggested to play an important role in the solubilization process. The present result represents a unique example of selective solubilization of a specific membrane protein from highly aggregated membranes. 相似文献
56.
H. Budzikiewicz K. Takeda K. Schreiber 《Monatshefte für Chemie / Chemical Monthly》1970,101(4):1003-1012
Zusammenfassung Der Einfluß von Substituenten in Ring D und F auf das Fragmentierungsverhalten von Spirostan-Derivaten wird diskutiert.
Mit 10 Abbildungen 相似文献
Mass spectrometric investigation of substituted steroid sapogenins
The influence of substitutents in ring D and F on the fragmentation behavior of spirostane derivatives is discussed.
Mit 10 Abbildungen 相似文献
57.
58.
59.
T. Minamisono S. Fukuda T. Ohtsubo M. Tanigaki A. Kitagawa M. Fukuda K. Matsuta Y. Nojiri S. Takeda 《Hyperfine Interactions》1993,78(1-4):191-194
Quadrupole effects in -NMR spectra of41Sc(I
=7/2–,T
1/2=0.596 s) implanted in a TiO2 single crystal were detected by use of a modified -NMR technique. Using the field gradient in the crystal determined by the pulsed-Fourier-transformed NMR of45Sc in TiO2, the quadrupole moment of41Sc has been determined as |Q(41Sc; 7/2–)|=166±8 mb. 相似文献
60.
Takahiro Makino Kimihiko Kato Hiroyuki Lyozumi Hiroe Honzawa Yoshiaki Tachiiri Mitsuo Hiramatsu † 《Photochemistry and photobiology》1996,64(6):953-956
Abstract— Ultraweak luminescence generated by sweet potato and nonpathogenic Fusarium oxysporum interactions associated with a defense response was detected by a photoncounting method using ultrahigh-sensitive photodetectors. The time-dependent intensity variation, the spectrum and the two-dimensional imaging of the ultraweak luminescence are indicative of the defense response of the sweet potato to F. oxysporum. The production of ipomeamarone as a phytoalexin means that F. oxysporum induced the defense response in the sweet potato. 相似文献