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481.
Y Ikai H Oka N Kawamura J Hayakawa M Yamada K Harada M Suzuki H Nakazawa 《Journal of chromatography. A》1991,541(1-2):393-400
A simple, rapid and reliable method for the determination of residual sulphonamide antibacterials (SAs) (sulphathiazole, sulphisozole, sulphamethoxazole, sulphadiazine, sulphamerazine, sulphadimidine, sulphamonomethoxine, sulphadimethoxine, sulphamethoxypyridazine and sulphaquinoxaline) in meat, fish and egg was developed using a combination of high-performance liquid chromatography (HPLC) and clean-up with an amino-type prepacked cartridge. SAs were extracted with ethyl acetate and applied to a Baker 10 amino cartridge. After elution from the cartridge, SAs were determined by HPLC. The recoveries at the level of 0.5 ppm were 73.7-99.1% and the detection limits were 0.05 ppm. The analysis time per sample was about 45 min. 相似文献
482.
Takeba K Fujinuma K Sakamoto M Miyazaki T Oka H Itoh Y Nakazawa H 《Journal of chromatography. A》2000,882(1-2):99-107
A simple method has been developed for the simultaneous determination of triclabendazole and its metabolites (sulphoxide and sulphone) in bovine milk by reversed-phase high-performance liquid chromatography (HPLC). A milk sample was homogenized with sodium sulfate anhydrous and acetonitrile, and centrifuged. The supernatant was isolated, rinsed with n-hexane saturated with acetonitrile, and evaporated. The residue was dissolved with 0.1 M potassium dihydrogenphosphate, and 0.1 M sodium hydrogencarbonate, and then cleaned up on a Bond Elut C18 cartridge. The three compounds were separated on a Capcell Pak C18 UG 120 (5 microm, 150x4.6 mm I.D.) column and determined by UV detection at 295 nm. The mobile phase was acetonitrile-0.05 M ammonium acetate (50:50), and the flow-rate was 0.8 ml/min at 40 degrees C. The mean recoveries (n=4) were 89.1-95.0% with a relative standard deviation of 1.1-2.6%. The detection limits were 0.004-0.006 microg/g in milk. The proposed method was used to monitor raw milk samples for the market, and applied to the analysis of milk samples from 10 cows which had been administered with triclabendazole to control the liver fluke. The confirmation of the triclabendazole and its metabolites in the above milk sample has been achieved by electrospray LC-MS for the first time. 相似文献
483.
2-Phenylheptamethyltrisilane as a model compound of polysilastyrene was irradiated at a high dose (1440 kGy) of γ-rays without any additive. The trisilane was found to be resistant to γ-rays, while it gave small amounts of Me6Si2, Me3SiSiMe2Ph, Me3SiH, Me3SiSiHMePh and (Me3Si)2 SiMeC6H4SiMe3. These products can be interpreted as being due to a chain contraction of the trisilane with the extrusion of methylphenylsilylene, a methyl migration with the extrusion of dimethylsilylene, a scission of an Si–Si bond due to an attack by hydrogen atoms, and a substitution of a hydrogen atom on the phenyl group by a trimethylsilyl radical. The same reactions, except the chain contraction, are observed in the cases of pentamethylphenyldisilane and 1,2-diphenyltetramethyldisilane. On the basis of the data obtained, the chemical behavior of polysilastyrene during the irradiation is discussed. 相似文献
484.
Yoshio Oka Takeshi Yao Shoichi Sato Naoichi Yamamoto 《Journal of solid state chemistry》1998,140(2):311
Ba analogues of hewettite (CaV6O16·9H2O) were synthesized by the hydrothermal methods. The compounds exhibit two phases formulated by BaV6O16·nH2O and Ba1+xV6O16·nH2O (x≈0.2,n≈3), and the structure of BaV6O16·nH2O has been determined from a single crystal study. It crystallizes in the orthorhombic systemPnmmwitha=12.162(3) Å,b=10.841(4) Å,c=17.035(4) Å, andZ=6 and the structure refinements led toR=0.066 andRw=0.076 for 1480 reflections withI>3σ(I). The structure is basically analogous to that ofγ-Li1+xV3O8or CaV6O16·9H2O, consisting of V6O16layers and interstitial hydrated Ba atoms. The V6O16layers stack along thecaxis with 8.518-Å spacing which is half of thecaxis; adjacent layers are mirror images of each other. Ba atoms reside in three kinds of sites with totally different oxygen coordinations. Their interlayer distributions result in another long period along thebaxis which is triple the ordinary 3.6-Å period of the hewettite compounds. This is the first single-crystal structural study of the synthetic hewettite compounds. 相似文献
485.
Direct oxidative cyclization of (eta2:eta2-CH2=CHCH2C6H4CHO)Ni(PR3) to form the nickelacycle and drastic acceleration of the cyclization by the addition of Me3SiOTf were observed. (eta2-PhCHO)Ni(PCy3)2 also reacted with Me3SiOTf to give (eta1:eta1-Me3SiOCH(Ph))Ni(PCy3)OTf. 相似文献
486.
Hirokazu Oka 《Semigroup Forum》1996,53(1):25-43
In this paper we study mild and classical solutions of the second order linear Volterra integrodifferential equation $$(VE^f )\left\{ {\begin{array}{*{20}c} {u''(t) = Au(t) + {\text{ }}\int_0^t {B(t - s)u(s)ds + f(t){\text{ }}for{\text{ }}t \in [0,T]} } \\ {u(0) = x{\text{ }}and{\text{ }}u'(0) = y,} \\ \end{array} } \right.$$ whereA is a closed linear operator whose domainD(A) is not necessarily dense in a Banach spaceX, and {B(t)|t≥0} is a family of bounded linear operators from the Banach space,D(A) endowed with the graph norm intoX. We also give two examples to illustrate the abstract results. 相似文献
487.
Hirokazu Oka 《Proceedings of the American Mathematical Society》1996,124(10):3143-3150
This paper is concerned with a class of complete second order linear differential equations in a Banach space. We show the existence and uniqueness of classical solutions of
488.
Efficient Synthesis of 2,11,20-Triaza[3.3.3](2,6)pyridinophane 总被引:1,自引:0,他引:1
Lee G Oka M Takemura H Miyahara Y Shimizu N Inazu T 《The Journal of organic chemistry》1996,61(23):8304-8306
489.
490.