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排序方式: 共有405条查询结果,搜索用时 921 毫秒
311.
Takaya Murakami Reiko Ishimaru Eriko Minami Yoshiaki Iwamuro Naoki Takamura Aya Torai Tsutomu Watanabe Akihiro Miki Munehiro Katagi Maiko Kusano Hitoshi Tsuchihashi Kei Zaitsu Satoshi Chinaka 《Journal of separation science》2023,46(3):2200681
Quick, easy, cheap, effective, rugged, and safe extraction strategies are becoming increasingly adopted in various analytical fields to determine drugs in biological specimens. In the present study, we developed two fully automated quick, easy, cheap, effective, rugged, and safe extraction methods based on acetonitrile salting-out assisted liquid-liquid extraction (method 1) and acetonitrile salting-out assisted liquid-liquid extraction followed by dispersive solid-phase extraction (method 2) using a commercially available automated liquid-liquid extraction system. We applied these methods to the extraction of 14 psychotropic drugs (11 benzodiazepines and carbamazepine, quetiapine, and zolpidem) from whole blood samples. Both methods prior to liquid chromatography–tandem mass spectrometry analysis exhibited high linearity of calibration curves (correlation coefficients, > 0.9997), ppt level detection sensitivities, and satisfactory precisions (< 8.6% relative standard deviation), accuracies (within ± 16% relative error), and matrix effects (81–111%). Method 1 provided higher recovery rates (80–91%) than method 2 (72–86%), whereas method 2 provided higher detection sensitivities (limits of detection, 0.003–0.094 ng/mL) than method 1 (0.025–0.47 ng/mL) owing to the effectiveness of its dispersive solid-phase extraction cleanup step. These fully automated extraction methods realize reliable, labor-saving, user-friendly, and hygienic extraction of target analytes from whole blood samples. 相似文献
312.
Satoshi Ishii Takayuki Nakane Takaya Furusawa Takashi Naka 《Crystal Research and Technology》2016,51(5):324-332
Single‐phase ZnAl2O4 nanoparticles were hydrothermally synthesized utilizing improvements to the preparation of the precursor materials. This synthesis differs from more general syntheses of ZnAl2O4 nanoparticles in that it minimizes the presence of ZnO impurities. The higher purity of our ZnAl2O4 nanoparticles allowed for more comprehensive X‐ray diffraction analysis as well as more sensitive spectroscopic evaluation. Moreover, pH control of the precursor solution dramatically improved the reproducibility of the synthesis. The lattice constant of the ZnAl2O4 samples synthesized by our technique is different from what is observed in particles fabricated using more common solid state reactions. This difference in lattice constants indicates the occurrence of a site exchange phenomenon between Zn2+ and Al3+ and/or oxygen deficiency. This suggests the possibility of tailoring novel functional spinel oxides for a wide array of future applications. 相似文献
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316.
Tatsuyoshi Ito Prof. Dr. Nobuharu Iwasawa Dr. Jun Takaya 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(29):12011-12015
An unprecedented photo-promoted skeletal rearrangement reaction of phosphine–borane frustrated Lewis pairs, o-(borylaryl)phosphines, involving cleavage of an unstrained sp2C–sp3C σ-bond is reported. The reaction realizes an efficient synthesis of cyclic phosphonium borate compounds. The reaction mechanism via a boranorcaradiene intermediate is proposed based on theoretical calculations. This work sheds light on the new photoreactivity of phosphine–borane FLPs. 相似文献
317.
We have developed a fundamentally new type of simple lattice Boltzmann (LB) model for the compressible Navier-Stokes equations based on the kinetic system proposed by Sone. The model uses the kinetic equation of free-molecular type in the streaming process and modifies the distribution function to its Chapman-Enskog type at each time step. Compared with the current LB models, the proposed model is superior in the following two points: (i) there are no inherent errors associated with the Knudsen number; (ii) any flow parameters, including three transport coefficients, can be chosen freely according to our convenience. Numerical tests and error estimates confirm the above statements. 相似文献
318.
Mariko Ono-Ogasawara Fumio Serita Mitsutoshi Takaya 《Journal of nanoparticle research》2009,11(7):1651-1659
As the production of engineered nanomaterials quantitatively expands, the chance that workers involved in the manufacturing
process will be exposed to nanoparticles also increases. A risk management system is needed for workplaces in the nanomaterial
industry based on the precautionary principle. One of the problems in the risk management system is difficulty of exposure
assessment. In this article, examples of exposure assessment in nanomaterial industries are reviewed with a focus on distinguishing
engineered nanomaterial particles from background nanoparticles in workplace atmosphere. An approach by JNIOSH (Japan National
Institute of Occupational Safety and Health) to quantitatively measure exposure to carbonaceous nanomaterials is also introduced.
In addition to real-time measurements and qualitative analysis by electron microscopy, quantitative chemical analysis is necessary
for quantitatively assessing exposure to nanomaterials. Chemical analysis is suitable for quantitative exposure measurement
especially at facilities with high levels of background NPs. 相似文献
319.
Straightforward Synthesis of 1,2‐Dicyanoalkanes from Nitroalkenes and Silyl Cyanide Mediated by Tetrabutylammonium Fluoride
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Dr. Kensuke Kiyokawa Takaya Nagata Junpei Hayakawa Prof. Dr. Satoshi Minakata 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(3):1280-1285
A straightforward synthesis of 1,2‐dicyanoalkanes by reacting nitroalkenes with trimethylsilyl cyanide in the presence of tetrabutylammonium fluoride is described. The reaction proceeds through a tandem double Michael addition under mild conditions. Employing the hypervalent silicate generated from trimethylsilyl cyanide and tetrabutylammonium fluoride is essential for achieving this transformation. Mechanistic studies suggest that a small amount of water included in the reaction media plays a key role. This protocol is applicable to various types of substrates including electron‐rich and electron‐deficient aromatic nitroalkenes, and aliphatic nitroalkenes. Moreover, vinyl sulfones were found to be good alternatives, particularly for electron‐deficient nitroalkenes. The broad substrate scope and functional group tolerance of the reaction makes this approach a practical method for the synthesis of valuable 1,2‐dicyanoalkanes. 相似文献
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