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31.
A thermometric titrator equipped with differential thermistor is used for the titration of molybdenum in sodium molybdate, potassium molybdate, magnesium molybdate, tetramethylammonium molybdate, and tetraethylammonium molybdate, based on their reactions with hydrochloric acid, and in ammonium paramolybdate, molybdic acid, and molybdenum trioxide, based on their reactions with sodium hydroxide. Orthomolybdates and ammonium paramolybdate were determined in the 0.5–0.005 M range; sufficient solid molybdic acid or molybdenum trioxide was taken to give a final 0.01–0.5 M solution in 20 ml of water. The method is simple and very quick. The standard deviation varies from 0.5 to 1.5% depending on the amount of sample taken. 相似文献
32.
A series of copper(II) complexes with tripodal polypyridylmethylamine ligands, such as tris(2-pyridylmethyl)amine (tpa), ((6-methyl-2-pyridyl)methyl)bis(2-pyridylmethyl)amine (Me(1)tpa), bis((6-methyl-2-pyridyl)methyl)(2-pyridylmethyl)amine (Me(2)tpa), and tris((6-methyl-2-pyridyl)methyl)amine (Me(3)tpa), have been synthesized and characterized by X-ray crystallography. [Cu(H(2)O)(tpa)](ClO(4))(2) (1) crystallized in the monoclinic system, space group P2(1)/a, with a = 15.029(7) ?, b = 9.268(2) ?, c = 17.948(5) ?, beta = 113.80(3) degrees, and Z = 4 (R = 0.061, R(w) = 0.059). [CuCl(Me(1)tpa)]ClO(4) (2) crystallized in the triclinic system, space group P&onemacr;, with a = 13.617(4) ?, b = 14.532(4) ?, c = 12.357(4) ?, alpha = 106.01(3) degrees, beta = 111.96(2) degrees, gamma = 71.61(2) degrees, and Z = 4 (R = 0.054, R(w) = 0.037). [CuCl(Me(2)tpa)]ClO(4) (3) crystallized in the monoclinic system, space group P2(1)/n, with a = 19.650(4) ?, b = 13.528(4) ?, c = 8.55(1) ?, beta = 101.51(5) degrees, and Z = 4 (R = 0.071, R(w) = 0.050). [CuCl(Me(3)tpa)][CuCl(2)(Me(3)tpa)]ClO(4) (4) crystallized in the monoclinic system, space group P2(1)/a, with a = 15.698(6) ?, b = 14.687(7) ?, c = 19.475(4) ?, beta = 97.13(2) degrees, and Z = 4 (R = 0.054, R(w) = 0.038). All the Cu atoms of 1-4 have pentacoordinate geometries with three pyridyl and one tertiary amino nitrogen atoms, and a chloride or aqua oxygen atom. Nitrite ion coordinated to the Cu(II) center of Me(1)tpa, Me(2)tpa, and Me(3)tpa complexes with only oxygen atom to form nitrito adducts. The cyclic voltammograms of [Cu(H(2)O)(Me(n)()tpa)](2+) (n = 0, 1, 2, and 3) in the presence of NO(2)(-) in H(2)O (pH 7.0) revealed that the catalytic activity for the reduction of NO(2)(-) increases in the order Me(3)tpa < Me(2)tpa < Me(1)tpa < tpa complexes. 相似文献
33.
L-Leucine, L-isoleucine and L-valine are determined by passage through a column of the enzyme immobilized on polystyrene beads, at pH 11.0. The NADH produced is monitored fluorimetrically. The detection limit is 0.1 nmol of L-leucine. 相似文献
34.
Inkjet printed (bio)chemical sensing devices 总被引:2,自引:0,他引:2
Nobutoshi Komuro Shunsuke Takaki Koji Suzuki Daniel Citterio 《Analytical and bioanalytical chemistry》2013,405(17):5785-5805
Inkjet printing has evolved from an office printing application to become an important tool in industrial mass fabrication. In parallel, this technology is increasingly used in research laboratories around the world for the fabrication of entire (bio)chemical sensing devices or single functional elements of such devices. Regularly stated characteristics of inkjet printing making it attractive to replace an alternative material deposition method are low cost, simplicity, high resolution, speed, reproducibility, flexibility, non-contact, and low amount of waste generated. With this review, we give an overview over areas of (bio)chemical sensing device development profiting from inkjet printing applications. A variety of printable functional sensor elements are introduced by examples, and the advantages and challenges of the inkjet method are pointed out. It is demonstrated that inkjet printing is already a routine tool for the fabrication of some (bio)chemical sensing devices, but also that novel applications are being continuously developed. Finally, some inherent limitations of the method and challenges for the further exploitation of this technology are pointed out. 相似文献
35.
Erika Toki Shiori Osaki Misato Nakamura Kazuki Tsuoka Nobutoshi Samejima Tetsuto Nakashima Rin Abe Takahiro Oyama Koichi Tsukiyama 《国际化学动力学杂志》2020,52(12):907-917
We conducted a simultaneous measurement of the potential of Cu2+, oxidation-reduction potential (ORP), and the chemiluminescence intensity in the luminol-H2O2-KSCN-CuSO4-NaOH system. Two types of chemiluminescence were identified: a very faint continuous chemiluminescence and a strong oscillating chemiluminescence. The correlation between the potential of Cu2+ and ORP was measured experimentally for the first time. The effect of the initial concentrations of Cu2+ and H2O2 on the overall chemiluminescence intensity and the oscillation frequency was investigated in detail. Time-dependent concentration variation of the chemical species existing in the reaction system was calculated using a Runge-Kutta method. Two elementary chemical reactions not considered previously were taken into consideration. The overall experimental behavior was well explainable with our simulation. Based upon the comparison of our simulation with the experiment, we proposed that the strong oscillating chemiluminescence was induced by the reaction of luminol with ·OS(O)CN. 相似文献
36.
Yoshiyuki Takahashi Nobutoshi Miyasaka Shigeo Tasaka Iwao Miura Shiro Urano Mitsuo Ikura Kunio Hikichi Takeshi Matsumoto Mizu Wada 《Tetrahedron letters》1982,23(49):5163-5166
Structures of the safflower red pigment carthamin and the yellow pigment safflor yellow A are shown to be expressed by 3 and 4 respectively, mainly on the basis of spectroscopic evidence. 相似文献
37.
Sanji T Yoshiwara A Sakurai H Tanaka M 《Chemical communications (Cambridge, England)》2003,(13):1506-1507
The first example of induced optical activity of oligosilanes within the internal cavity of gamma-cyclodextrins is reported. 相似文献
38.
Tsuneo Kurita Nagayoshi Kasashima Hiroki Yamakiri Nobuhito Ichihashi Nobutoshi Kobayashi Kiwamu Ashida Shinya Sasaki 《Optics and Lasers in Engineering》2011,49(9-10):1216-1223
An IC is generally decapsulated with wet etching technology. The influences of environment and worker's health in usage and waste of the chemicals are seen as problems. Improvement of processing time is also needed. In order to overcome them, the laser processing technology is applied to IC decapsulation. In this paper, the relationship between processing condition and the processed surface quality is reported to select a suitable laser source. In addition, the new IC decapsulation technology, which is the combination of laser and wet etching, is proposed. To achieve the complex machining, firstly, the method of measuring the reflection light intensity of the laser is proposed to estimate the residual molding thickness. Secondly, the relationship between intensity of reflected laser and mold thickness to IC is shown to construct a mold thickness monitoring system. Finally, processing time and the volume of chemical solution used a process are compared with a conventional wet etching process. 相似文献
39.
Fujii S Masuno H Taoda Y Kano A Wongmayura A Nakabayashi M Ito N Shimizu M Kawachi E Hirano T Endo Y Tanatani A Kagechika H 《Journal of the American Chemical Society》2011,133(51):20933-20941
We report here the design and synthesis of a novel vitamin D receptor (VDR) agonist whose hydrophobic core structure is p-carborane (1,12-dicarba-closo-dodecaborane, an icosahedral carbon-containing boron cluster having remarkable thermal and chemical stability and a characteristically hydrophobic B-H surface). This carborane-based VDR ligand exhibited moderate vitamin D activity, comparable to that of the natural hormone, despite its simple and flexible structure. X-ray structure analysis provided direct evidence that the carborane cage binds to the hydrophobic surface of the ligand-binding pocket of the receptor, promoting transition to the active conformation. These results indicate that the spherical B-H surface of carborane can function efficiently as a hydrophobic anchor in binding to the receptor surface, thereby allowing induced fitting of the three essential hydroxyl groups on the alkyl chains to the appropriate positions for interaction with the VDR binding site, despite the entropic disadvantage of the flexible structure. We suggest that carborane structure is a promising option in the design of novel drug candidates. 相似文献
40.
Masatake Ozawa Kazue Tani Masaki Tachibana Hitoshi Koizumi Nobutoshi Kiba 《Chromatographia》2010,72(3-4):313-316
The retention behavior of purine and purine-like compounds on titania was investigated in order to elucidate the strong retention of purine on titania. It was verified that, as expected, the strong retention stemmed from the formation of a chelate ring using the two nitrogen atoms N3 and N9 with titania. Purine has two possible tautometric forms because of proton tautomerism between N7 and N9. Hence, the lone pair of either of the two nitrogen atoms could be located immediately in an sp2 orbital. Therefore, it was found that the lone pairs of N3 and N9 must be located in an sp2 orbital, and the location is essential to forming the chelate with titania. Moreover, the effect of the presence of methanol and acetonitrile in the mobile phase on retention was also investigated. The retention strength increased with their content, but the tendency of this increase was different for the two organic solvents. It was concluded that the difference stems from the differing degrees of strength of the ligands, which includes the analytes and the solvents, as a result of competing with each other. Water and methanol acted as ligands strong enough to compete with the analytes, but acetonitrile did not, probably because it lacks hydroxy groups, which have a strong affinity for titania. 相似文献