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1.
S. Ambe K. Yashiki H. Maeda S. Enomoto T. Ozaki F. Ambe 《Journal of Radioanalytical and Nuclear Chemistry》1998,236(1-2):181-185
Separation by means of supported liquid membranes is a useful method for the preparation and preconcentration of radioactive
nuclides. The permeation of rare earth elements through a bis(2-ethylhexyl) hydrogen phosphate-decalin membrane supported
on a microporous polytetrafluoroethylene sheet was studied using a multitracer containing radioactive nuclides of Sc, Zr,
Nb, Hf, Ce, Pm, Gd, Yb, and Lu. Permeation rates of these elements from feed solutions of various acidity to receiving solutions
of 0.5 mol·dm−3 HCl were determined simultaneously. The feed solution at pH 1.4 gave the highest permeation rate for Ce, Pm, and Gd, amounting
to about 95% of permeation for Ce and Pm, 80% for Gd, and 10% for Yb in 21 h. Scandium, Zr, Nb, Hf, and Lu were not transported
at all from the feed solution. Permeation rates of Yb and Lu from the feed solution at pH 1.4 to receiving solutions of 0.75,
1.0, 2.3, and 4.0 mol·dm−3 HCl increased with the concentration. The results obtained indicate that the light rare earth elements can be separated from
the heavy ones by this method. 相似文献
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N Noda Y Yashiki T Nakatani K Miyahara X M Du 《Chemical & pharmaceutical bulletin》2001,49(7):930-931
The novel quinoline alkaloid scolopendrine was isolated from the centipede, Scolopendra subspinipes mutilans L. Koch. The structure was determined to be 2-hydroxy-7-[(4-hydroxy-3-methoxyphenyl)methyl]-3-methoxy-8-quinolyl sulfate on the basis of high-resolution electron-spray ionization mass spectroscopy and two-dimensional NMR spectral data. Unlike quinoline alkaloids so far reported, scolopendrine is unique in having a 7-benzyl moiety in the quinoline ring. 相似文献
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H Toguchi Y Ogawa K Iga T Yashiki T Shimamoto 《Chemical & pharmaceutical bulletin》1990,38(10):2792-2796
To obtain information as to a suitable formulation of ethyl 2-chloro-3-[4-(2-methyl-2-phenylpropyloxy)-phenyl]propionate (AL-294), an antihyperlipidemic drug of low water solubility, the bioavailability after its oral administration in various dosage forms was evaluated in rats and dogs. After AL-294 was administered orally, AL-294 acid (2-chloro-3-[4-(2-methyl-2-phenylpropyloxy)phenyl]propionic acid), which is a metabolite of AL-294, was detected in the plasma. Therefore, absorbability of AL-294 was evaluated using plasma AL-294 acid levels. AL-294 in an oil solution or in a gelatin capsule showed poor absorption, whereas it's absorption was greatly enhanced in the form of an emulsion. The postprandial administration also showed better absorption. The elimination rate of AL-294 acid from the plasma after oral administration of the emulsion was similar to that after intravenous administration of a sodium salt of AL-294 acid. 相似文献
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An automated high-performance liquid chromatographic method using column switching was established for the simultaneous determination of cefotiam (I) and delta 3-cefotiam (II) in human plasma after oral administration of cefotiam hexetil dihydrochloride. The method allowed the determination of analytes in plasma by the direct injection of diluted specimen with phosphate buffer. The analytes were enriched onto the C18 short pretreatment column by 0.05 M phosphate buffer (pH 7.7), while proteins and endogenous hydrophilic substances in plasma were washed off to waste. The enriched analytes were then back-flushed onto the analytical C18 column, separated by a mixture of 0.05 M phosphate buffer (pH 7.7)-acetonitrile (88:12, v/v) and detected by the ultraviolet absorbance at 254 nm. Recoveries from spiked plasma were quantitative, and the coefficients of variation were below 4%. The lower detection limits in plasma were 10 ng/ml for both I and II. Concentrations of I and II in plasma determined by the present method were in good agreement with those obtained by the conventional deproteinization method. 相似文献
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Column-switching techniques for high-performance liquid chromatography of two acidic drugs, ibuprofen and mefenamic acid, in human serum with short-wavelength ultraviolet detection are described. The method involved extraction of the analyte from acidified serum followed by the chromatographic analysis using column switching. Three ODS columns were used each with different mobile phase, utilizing the difference of ion-pair formation or of ionization caused by pH change. The method offered high sensitivity and selectivity, with short-wavelength ultraviolet detection at 221 nm for ibuprofen and at 219 nm for mefenamic acid. The detection limits were 0.5 ng/ml (2.4 pmol/ml) for ibuprofen and 0.1 ng/ml (0.4 pmol/ml) for mefenamic acid using 1 ml of serum, both at a signal-to-noise ratio of 3. With some modifications, the principle of the method would be applicable to other acidic compounds in biological fluids. 相似文献
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Yasutoshi Yashiki Seiichi Kouketsu Shinsuke Miyajima Akira Yamada Makoto Konagai 《Journal of Non》2008,354(19-25):2355-2358
The influence of plasma power and substrate temperature on the structure of nanocrystalline germanium carbon thin films was investigated. Films were deposited by the very high frequency plasma chemical vapor deposition technique using hydrogen diluted monomethylgermane (MMG). Plasma power strongly affected the decomposition of hydrogen and MMG. Crystalline volume fraction and bonding states of the atoms in the films depends on plasma power and substrate temperature. FT-IR measurements also revealed that Ge–Hn and CHn bonds are sensitive to these factors. 相似文献
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A simple method for the analysis of nereistoxin and its metabolites in human serum using headspace solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) is developed. A vial containing a serum sample, 5M sodium hydroxide, and benzylacetone (internal standard) is heated to 70 degrees C, and an SPME fiber is exposed for 30 min in the headspace of the vial. The compounds extracted by the fiber are desorbed by exposing the fiber in the injection port of the GC-MS. The calibration curves show linearity in the range of 0.05-5.0 micrograms/mL for nereistoxin and N-methyl-N-(2-methylthio-1-methylthiomethyl)ethylamine, 0.01-5.0 micrograms/mL for S,S'-dimethyl dihydronereistoxin, and 0.5-10 micrograms/mL for 2-methylthio-1-methylthiomethylethylamine in serum. No interferences are found, and the analysis time is 50 min for one sample. In addition, this proposed method is applied to a patient who attempted suicide by ingesting Padan 4R, a herbicide. Padan 4R contains 4% cartap hydrochloride, which is an analogue of nereistoxin. Nereistoxin and its metabolites are detected in the serum samples collected from the patient during hospitalization. The concentration ranges of nereistoxin in the serum are 0.09-2.69 micrograms/mL. 相似文献
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T Yashiki T Matsuzawa M Yamada T Kondo H Mima 《Chemical & pharmaceutical bulletin》1971,19(5):881-891