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151.
Miho Shinomiya 《International journal of environmental analytical chemistry》2013,93(8):858-871
A multi-residue method using liquid chromatography coupled to triple quadrupole tandem mass spectrometry (LC-MS/MS), associated with solid-phase extraction (SPE), was developed for the determination of 21 pesticides in water samples. The compounds investigated are used for the maintenance of golf courses and ordinarily measured by gas chromatography-mass spectrometry (GC-MS). Electrospray ionisation (ESI) was applied to all compounds, and LC and MS conditions were optimised to measure them under SRM mode. This method showed excellent linearity ranges for all pesticides, with correlation coefficients greater than 0.996. Two kinds of extraction cartridges, namely, styrene divinylbenzene polymer (Sep-Pak PS-2) and divinylbenzene-N-vinylpyrrolidone copolymer (Oasis HLB), were tested and the extraction conditions were optimised. All the pesticides were determined using acetonitrile and ethyl acetate as eluents in both cartridges, and good recoveries (>77%) and repeatability with low relative standard deviations (RSDs, <12%) were achieved from ultra-pure water. In addition, satisfactory recoveries (>76%) and low intra-day and inter-day RSDs (<15%) of all pesticides were also obtained with the Sep-Pak PS-2 cartridge when using river water. The method limits of detection (LODs) ranged between 0.068 (diazinon) and 3.9 (triclopyrbutoxyethyl)?ng?L?1. The analytical method was successfully applied for the determination of pesticides in surface river water. 相似文献
152.
Moriyasu T Minowa K Sakamoto M Kishimoto K Kadoi H Nakajima J Mori K Ogino S Fukaya H Shida Y 《Journal of AOAC International》2011,94(6):1770-1777
An analog of aildenafil, which is a potent and highly selective inhibitor of phosphodiesterase 5, was found in a dietary supplement marketed for enhancement of sexual function. The compound was isolated by silica gel column chromatography, and its structure was identified by means of 13C-NMR spectrometry, 1H-NMR spectrometry, high-resolution MS, and X-ray structure determination. The compound was identified to be sulfoaildenafil (other names: thioaildenafil, dimethyl sildenafil thione, and thiomethisosildenafil). Sulfoaildenafil is very similar to the compound thiohomosildenafil. As it is difficult to distinguish between them by LC-photodiode array detector analysis, ultra-performance LC (UPLC)/MS, ion trap LC/MS/MS (LC/IT-MS/MS), and GC/MS were performed. The mass spectra of thiohomosildenafil by UPLC/MS and LC/IT-MS/MS showed mass fragments of m/z 58, 72, and 355, and the mass spectrum by GC/MS showed mass fragments of m/z 56, 72, and 420. Some of these fragments had low intensities, but they were useful for distinguishing between the two compounds. The relationship between aildenafil (other names: dimethylsildenafil and methisosildenafil) and homosildenafil is similar to that between sulfoaildenafil and thiohomosildenafil. Therefore, these compounds were also examined. 相似文献
153.
Asakawa T Hiza A Nakayama M Inai M Oyama D Koide H Shimizu K Wakimoto T Harada N Tsukada H Oku N Kan T 《Chemical communications (Cambridge, England)》2011,47(10):2868-2870
A practical synthesis of nobiletin, a polymethoxylated citrus flavone, was accomplished by utilizing our novel flavone synthesis. Synthetic nobiletin was labelled by selective demethylation and rapid incorporation of (11)C atom. Positron emission tomography images successfully visualized the brain distribution, which may provide therapeutic benefits in the treatment of Alzheimer's disease. 相似文献
154.
Hiroshi Moriwaki Miho Ishitake Shusaku Yoshikawa Hidekazu Miyakoda Jean-Fran?ois Alary 《Analytical sciences》2004,20(2):375-377
We describe a method for the simultaneous determination of 12 kinds of polycyclic aromatic hydrocarbons (PAHs) in sediment based on liquid chromatography-atmospheric pressure photoionization-mass spectrometry (LC/APPI/MS). The method consists of PAH extractions by ultrasonics, clean-up by a solid-phase extraction procedure and determination by LC/APPI/MS. The limits of the determination for PAHs in sediment using the proposed method ranged from 0.06 to 0.9 mg/kg. PAHs were detected by this method in sediment samples on the mg/kg level. 相似文献
155.
156.
We construct a set of exact ground states with a localized ferromagnetic domain wall and an extended spiral structure in a quasi-one-dimensional deformed flat-band Hubbard model. In the case of quarter filling, we show the uniqueness of the ground state with a fixed magnetization. The ground states with these structures are degenerate with the all-spin-up and all-spin-down states. This property of the degeneracy is the same as the domain wall solutions in the XXZ Heisenberg–Ising model. We derive a useful recursion relation for the normalization of the domain wall ground state. Using this recursion relation, we discuss the convergence of the ground state expectation values of arbitrary local operators in the infinite-volume limit. In the ground state of the infinite-volume system, the translational symmetry is spontaneously broken by this structure. We prove that the cluster property holds for the domain wall ground state and excited states. We also estimate bounds of the ground state expectation values of several observables, such as one- and two-point functions of spin and electron number density. 相似文献
157.
The hydrolysis-precipitation equilibrium reaction of aqueous gallium(III) solution was investigated in 0–3 mol-kg-1 NaCl media at low pH at 100°C using a pressure-tight glass vessel. All precipitates were identified as GaOOH. The results
were analyzed with a nonlinear least-squares computer program to obtain the solubility product Kso for gallium(III) oxyhydroxide using a single-parameter type of Debye-Hückel equation. The value of log Kso for GaOOH(s) + 3H+ ⇆ Ga3+ + 2H2O was -0.60 at 100°C. The solubility product calculated from thermodynamic data was compared with the experimental result. 相似文献
158.
Hiroyoshi Kawakami Kazue Hiraka Miho Tamai Aiko Horiuchi Akihiko Ogata Tomomi Hatsugai Aritomo Yamaguchi Kenichi Oyaizu Makoto Yuasa 《先进技术聚合物》2007,18(1):82-87
In this article the novel design of an anticancer drug delivery system is reported based on a pH‐sensitive liposome retaining the Fe‐porphyrin as a superoxide dismutase(SOD) mimic. The liposomes contained cationic/anionic lipid combinations and were composed of Fe‐porphyrin, L ‐α‐phosphatidylcholine (DMPC), dimethylditetradecylammonium bromide (DTDAB), sodispdum oleate (OANa), and Tween‐80. The size of the liposome was approximately 30 nm. The EC50 value (the effective concentration of compound required to produce a 50% lethal dose against cells) of the liposome was found to be significantly smaller than that of cisplatin as the control drug, suggesting that the liposome showed a high cytotoxicity toward the cancer cells. This is due to the fact that the pH‐sensitive liposome rapidly corresponds to the acidic environments of the endosomes and is unstable, and the Fe‐porphyrin is delivered into the cytosol. This result suggests that O may be useful as a target molecule to induce the selective death of cancer cells and that a pH‐sensitive liposome retaining Fe‐porphyrin as an SOD mimic is a new class of anticancer agent. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
159.
AlCl(3) solution was analyzed at concentrations from 0.02 to 100 mM using an electrospray ionization quadrupole mass spectrometer (ESI-Q-MS), and the dissolution state of aluminum ions is discussed. Results obtained using ESI-Q-MS were consistent with those obtained using (27)Al nuclear magnetic resonance ((27)Al NMR). Aluminum species existed mainly as positively charged monomeric aluminum hydroxide coordinated with several water molecules in solution. The complexation of chloride ions by aluminum ions differed between the positive and negative ion modes. Chemical reactions that partially modified chemical forms of species through ESI-Q-MS measurement were also observed. In the same aluminum chloride solution, using ESI-TOF-MS and ESI-Q-MS/MS studies, the disagreement of the reports is discussed. It is concluded that ESI-TOF-MS might show also the gas-phase reaction in the mass spectrometer but the dissolution state of aluminum species can be shown by ESI-Q-MS. 相似文献
160.
Noguchi T Tanaka N Nishimata T Goto R Hayakawa M Sugidachi A Ogawa T Asai F Fujimoto K 《Chemical & pharmaceutical bulletin》2007,55(10):1494-1504
A series of cinnamylindoline derivatives were synthesized, and their factor Xa (FXa) inhibitory activities and selectivity over trypsin were evaluated. Among them, some novel derivatives showed potent FXa inhibitory activities and good selectivity over trypsin. Especially, (E)-2-{5-[1-(acetimidoyl)piperidin-4-yloxy]-2-[2-(5-amidino-2-hydroxyphenyl)ethen-1-yl]indolin-1-ylsulfonyl}acetic acid (22f) having 2-hydroxycinnamyl moiety exhibited the most potent FXa inhibitory activity in vitro. Furthermore, 22f also exhibited potent anticoagulant activities in vitro. 相似文献