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81.
Uchiyama K Kondo M Yokochi R Takeuchi Y Yamamoto A Inoue Y 《Journal of separation science》2011,34(13):1525-1530
A simple, selective and rapid analytical method for determination of trimethoprim (TMP) in honey samples was developed and validated. This method is based on a SPE technique followed by HPLC with photodiode array detection. After dilution and filtration, aliquots of 500 μL honey samples were directly injected to an on-line SPE HPLC system. TMP was extracted on an RP SPE column, and separated on a hydrophilic interaction chromatography column during HPLC analysis. At the first detection step, the noise level of the photodiode array data was reduced with two-dimensional equalizer filtering, and then the smoothed data were subjected to derivative spectrum chromatography. On the second-derivative chromatogram at 254 nm, the limit of detection and the limit of quantification of TMP in a honey sample were 5 and 10 ng/g, respectively. The proposed method showed high accuracy (60-103%) with adequate sensitivity for TMP monitoring in honey samples. 相似文献
82.
Chen L Han X Yang J Zhou J Song W Zhao B Xu W Ozaki Y 《Journal of colloid and interface science》2011,360(2):482-487
We have employed the proposed Silica-Silver Core-Shell (SSCS) SERS-active substrates to detect four model proteins: lysozyme (a protein without chromophore), cytochrome c (a protein with chromophore of heme), fluorescein isothiocyanate (FITC)-anti human IgG (labeled with FITC) and atto610-biotin/avidin (recognition with labeled small molecules). SERS spectra of these proteins and Raman labels on the SSCS substrates show both high sensitivity and reproducibility, which are due to electromagnetic SERS enhancement with additional localization field within closely packed Ag nanoparticles decorated on the SiO(2) nanoparticles and the aggregation of SiO(2)@Ag particles. We have found that the SERS intensities of atto610-biotin/avidin adsorbed on the SSCS substrates are about 20 times stronger than those from Ag plating on Au-decorated substrate. Moreover, the broad surface plasmon resonance (SPR) of the proposed substrates will extend SERS applications to more biological molecules with different laser excitations. 相似文献
83.
Crown ether-type macrocycles consisting of an enantiopure biarenol derivative and an oligoethylene glycol were synthesized by the Lewis acid-mediated tandem Claisen rearrangement. This is the first example of the successful application of the tandem Claisen rearrangement to the synthesis of enantiopure macrocyclic biarenol derivatives. The enantiopure macrocyclic biarenols were found to form 1:1 complexes with amino acid salts and to discriminate their chirality. 相似文献
84.
Michinori Karikomi Mari Yamada Hirohiko Houjou Kazuhisa Hiratani Tadao Uyehara 《Tetrahedron letters》2005,46(35):5867-5869
Oxidative coupling reaction of both 3-hydroxychrysene and 2-hydroxybenzo[c]phenanthrene by using Cu(NO3)2-3H2O under atmospheric air is described. The former gave the aimed coupled biaryl derivative. However, the latter gave a further oxidized helical quinone derivative. The unique helical structure was characterized by X-ray and NMR analysis. 相似文献
85.
Novel stereospecific isomerization of 2-(1-bromoalkyl)-1-sulfonylaziridines into 2-(bromomethyl)-3-alkyl-1-sulfonylaziridines using magnesium bromide is described. The suitable choice of solvent led to good yields and diastereoselectivites. 相似文献
86.
Hideo Kojima Kazuyoshi Ozaki Noboru Matsumura Hiroo Inoue 《Journal of heterocyclic chemistry》1990,27(6):1845-1846
7-Substituted 2,3-bis(isopropylthio)naphth[1,8-bc]azepines 3a-c were synthesized in good yields by the reactions of 5-substituted 1-naphthylamines 2a-c with tris(isopropylthio)cyclopropenylium perchlorate ( 1 ) in acetonitrile under reflux. This reaction proceeds through the facile ring opening of 1 , followed by the intermediary formation of iminium salts 5a-c and then intramolecular cyclization. 相似文献
87.
T. Itoh K. Hashimoto Y. Kikkawa A. Ikehata Y. Ozaki 《光散射学报》2005,17(3):299-302
pacc:5240F,7830Weinvestigatedpolarizationdependencesof surfaceenhancedresonanceRamanscattering(SERRS)andsurfaceplasmonresonance(SPR)toidentifytheSERRSyieldingSPRbands.We alsostudiedSERRSexcitationspectraforsingle Agnano-aggregateswiththeSPRbandstoex plore… 相似文献
88.
Terrestrial carbonate deposits with a banded layer structure can be good tools for the extraction of past environmental information on global and local scales using trace element concentrations and stable isotope ratios. The absolute age dating is most important for the reconstruction of an environmental chronicle. The measurements of fluorescent annual bandings in stalagmites using a microscopic spectrofluorometer with an XY-stage can be a convenient dating method and are especially effective for young samples whose absolute age is very difficult to be determined by other methods. The number of annual bandings was objectively counted using a personal computer. The optimal conditions for the measurements are discussed. The annual banding in stalagmites is caused by the seasonal differences in the fulvic acid concentrations in the dripping water which forms speleothems. 相似文献
89.
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