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1.
Kazuhiko Nakano Toshihiro Nakamura Izumi Nakai Akira Kawase Makoto Imai Mikio Hasegawa Yohichi Ishibashi Isamu Inamoto Kazuhuyu Sudou Masaru Kozaki Akira Tsuruta Akihiro Ono Kazutoshi Kakita Mamoru Sakata 《Analytical sciences》2006,22(9):1265-1268
The Japan Society for Analytical Chemistry has developed some new plastic certified reference materials (CRMs) for the analysis of mercury in polyester disks using XRF analysis. These CRMs (named as JSAC 0621-0625) were prepared by casting polyesters including a toluene solution of organometallic compounds as a standard. Concentrations of the five levels of mercury ranged from 0 to 250 mg/kg. Homogeneity tests of prepared disks had shown excellent results. Interlaboratory comparison study for the certification was performed by 15 laboratory participants. The z-scores in robust statistical method was applied for the evaluation of outliers. The certified values were assigned after discarding outliers. The uncertainties of certified values were determined as the confidence levels of 95%. 相似文献
2.
Sachiko Yamada Keiko Nakayama Hiroaki Takayama Toshimasa Shinki Tatsuo Suda 《Tetrahedron letters》1984,25(30):3239-3242
(25)-25,26-Dihydroxy-23-oxovitamin D3 was synthesized efficiently and stereoselectively, and it was converted enzymatically to (25)-1α,25,26-trihydroxy-23-oxovitamin D3, a putative metabolite of 1α,25-dihydroxyvitamin D3. The spectral and chemical properties of (25)-25,26-dihydroxy-23-oxovitamin D3 and its 1α,hydroxylated derivative disagree with those reported for the isolated metabolite. 相似文献
3.
Ohne Zusammenfassung 相似文献
4.
The retention behavior of lymphocyte subpopulations, B cell, T cell and null cell, derived from rat spleen to polyamine-graft-poly(2-hydroxyethyl methacrylate) copolymer (HA) surface was investigated, focusing on the conformational transition of the polyamine side chain as well as the protonation of amino groups in the polyamine grafts. Furthermore, the availability of HA was discussed as a column adsorbent for separation of lymphocyte subpopulations derived from spleen. The conformational transition of polyamine grafts significantly influenced the mode of retention of lymphocyte subpopulations. When polyamine grafts existed in an aggregated conformation (protonatin degree α < 0.5), the retention of lymphocyte subpopulations was decreased in the order B cell> null cell> T cell. On the other hand, when polyamine existed in an extended conformation into the aqueous interior from the matrix interface (α > 0.5), T cell retention became greater than null cell retention, resulting in a decreased B cell> T cell> null cell order. These results indicate that the differential retention of spleen lymphocyte subpopulations is attributed to their differential responses to the change in matrix interface accompanied by the protonation of amino groups. Furthermore, spleen lymphocytes were compared with lymph node lymphocytes in terms of resolution efficacy by an HA copolymer column. 相似文献
5.
A sensitive method for the determination of nicotinic acid in serum is described which employs high-performance liquid chromatography with fluorescence detection. Nicotinic acid and 2-chloronicotinic acid as an internal standard in deproteinized serum are reacted with N,N'-dicyclohexyl-O-(7-methoxycoumarin-4-yl)methylisourea in acetone to give the corresponding fluorescent 4-hydroxymethyl-7-methoxycoumarin esters. The compounds are separated by reversed-phase chromatography on LiChrosorb RP-18 with isocratic elution using aqueous acetonitrile containing a small amount of sodium 1-hexanesulphonate as a mobile phase. The detection limit of nicotinic acid in serum was 0.2 nmol/ml. The method requires only 100 microliters of serum. 相似文献
6.
A sensitive method for the assay of monoamine oxidases A and B is described which employs high-performance liquid chromatography with fluorescence detection. Rat brain mitochondria were used as a preparation of the enzymes. p-Sulfamoylbenzaldehyde and benzaldehyde formed enzymatically from p-sulfamoylbenzylamine (the substrate of monoamine oxidase A) and benzylamine (the substrate of monoamine oxidase B), respectively, are converted simultaneously into fluorescent compounds with 2,2'-dithiobis(1-aminonaphthalene). These compounds are separated by reversed-phase chromatography on mu Bondapak CN. The limits of detection for p-sulfamoylbenzaldehyde and benzaldehyde formed enzymatically are 30 and 10 pmol per assay tube, respectively. 相似文献
7.
Masato ItoAkihide Osaku Sachiko KitaharaMakoto Hirakawa Takao Ikariya 《Tetrahedron letters》2003,44(40):7521-7523
A ternary catalyst system of Cp*RuCl(cod)-2-diphenylphosphinoethylamine-KOt-Bu (Cp*=η5-C5(CH3)5, cod=1,5-cyclooctadiene) causes rapid racemization of chiral non-racemic sec-alcohols, which results from the reversible hydrogen transfer between sec-alcohols and ketones. Both tertiary phosphine and primary amine functionalities in the ligand are responsible for the high rate. 相似文献
8.
K. Kitamura Hideyuki Mano Yoshie Shimamoto Yoshihiro Tadokoro Koji Tsuruta Shinji Kitagawa 《Analytical and bioanalytical chemistry》1997,358(4):509-513
The second-derivative spectra of chlorpromazine (CPZ) or triflupromazine (TFZ) in buffer solutions (pH 7.4) containing various amounts of BSA (the reference solutions contained the same amount of BSA) showed derivative isosbestic points. The residual background signals derived from incomplete suppression of BSA signals can be entirely eliminated in the second-derivative spectra and BSA has spectrophotometrically one kind of binding site for CPZ or TFZ. The fractions of the drugs bound to BSA were calculated from the derivative intensity differences (ΔD values) of CPZ or TFZ before and after the addition of BSA. Scatchard plot experiments suggested that the binding of the drugs to BSA could be explained as a partition like non-specific binding model. The association constants (K) of CPZ or TFZ with BSA were calculated from the ΔD values according to the non-specific binding model by a nonlinear least-squares method. The K values were almost constant for all of the drug concentrations studied, and good reproducibility was obtained. The fractions predicted by the K values were in good coincidence to the observed values. These results confirm the usefulness of the proposed derivative method which does not need any separation procedures. 相似文献
9.
10.
Sagara T Nagata K Tsuruta H Nakashima N 《Chemical communications (Cambridge, England)》2002,(18):2116-2117
Potential-dependent dynamic adsorption-desorption and reorientation of a 4-pyridyl modified PAMAM G2 dendrimer at a Au(111) electrode has been demonstrated. 相似文献