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1.
M. J. Gaylard G. C. MacLeod D. P. Smits M. E. West D. J. Walt 《Journal of chemical crystallography》1993,23(9):763-763
Future contributions toJournal of Crystallographic and Spectroscopic Research 相似文献
2.
Cerium(III) ions in dilute sulphuric acid medium exhibit a characteristic fluorescence which has its excitation maximum at 260 nm and its fluorescence emission maximum at 350 nm. By utilising the osmium-catalysed redox reaction between cerium(IV) and arsenic(III), microgram amounts of arsenic (7.5–37.5 μg) may be determined by spectrofluorimetric measurement of the ceriurm(III) produced. The principle may be applied to the determination of several other ions which cannot yet be determined by direct spectrofluorimetry, e.g.. Fe(II) (5.6–28 μg), oxalate (8.8–44μg). Osmium(VIII) (0.05–0.2 μg) and iodide (0.6–2.5 μg) may be determined by their catalytic action. 相似文献
3.
The application of an inductively coupled high-frequency plasma source to the determination of iodine, mercury, arsenic and selenium by atomic emission spectrometry at wavelengths less than 200 nm is described. Optimal conditions have been established, and the spectral interference effects at different atomic lines for each element have been investigated. With the type of instrumentation employed, the determination of iodine at 183.04 nm, mercury at 184.96 nm, arsenic at 189.0 nm and selenium at 196.09 nm is recommended to minimize spectral interferences. No chemical or physical interferences resulting from the influence of foreign ions on the solute vaporization process have been noted. 相似文献
4.
Zusammenfassung Leitfähigkeitsmessungen an Et4NCl-Lösungen zeigen die Gültigkeit derBjerrumschen Theorie in PhPOCl2; die Dissoziationskonstante beträgt 1,5·10–2. FeCl3 verhält sich nicht wie eine Ionenverbindung, doch ähnlich wie in POCl3. Zur Verfolgung von Ionenreaktionen wurden konduktometrische Titrationen ausgeführt. ZnCl2 und AlCl3 geben 2 Chloridionen, BCl3, TiCl4, SnCl4 und PCl5 je 1 Chloridion an die Akzeptoren FeCl3 oder SbCl5, ab. In Gegenwart von polaren Chloriden nehmen BCl3, AlCl3, FeCl3, PCl5 und SbCl5 je 1 Chloridion, ZnCl2, TiCl4 und SnCl4 je nach Angebot 1 oder 2 Chloridionen auf. Sowohl die Chlorometallate, als auch die Chloroniumverbindungen sind im gleichen Ausmaß wie Et4NCl ionisiert.Mit 4 Abbildungen2. Mitt.:M. Baaz, V. Gutmann, M. Y. A. Talaat undT. S. West, Mh. Chem.92, 150 (1961).Herrn Prof. Dr.L. F. Audrieth zum 60. Geburtstag gewidmet. 相似文献
5.
The high frequency oscillator provides an excellent means of detecting the end-points of titrations performed with ethylenediaminetetraacetic acid or its salts. The determination of various divalent metals is reported, based on both direct and indirect titrations. Because of the great sensitivity of the method it is possible to determine cobalt, nickel, copper (II), zinc, cadmium, lead and manganese (II) in concentration ranges of 1/1000 to 1/6000M. 相似文献
6.
An indirect spectrophotometric method is proposed for the determination of cyanide down to 0.2 ppm. It is based on the fact that cyanide prevents the formation of the strongly absorbing ternary complex between silver(I), 1,10-phenanthroline and Bromopyrogallol Red in nearly neutral aqueous solution. Among 17 cations examined, only mercury(II) could not be tolerated. Zinc, cadmium and cobalt interfered only when present in large amounts. A 1000-fold molar excess (over cyanide) of 14 anions can also be tolerated. Bromide, iodide and thiocyanate interference is overcome by addition of lead nitrate, ammonium sulphate and barium nitrate, followed by centrifugation. 相似文献
7.
[reaction: see text] The silyl group of 2-silylpyrrolidines such as 1 plays several critical roles: a stereochemical control element in a facially selective carbenoid addition to the ring nitrogen, a stereochemical "placeholder" during regioselective 1,2-migration with retention by the resulting spirocyclic ammonium ylide, and a hydroxyl surrogate for an eventual stereoselective Fleming-Tamao oxidation. This chemistry represents a novel use of the Stevens rearrangement and offers a short, enantioselective route to hydroxylated quinolizidines such as 3 from Boc-pyrrolidine. 相似文献
8.
Atomic fluorescence in flames is measured by an adaptation of a commercially available flame spectrophotometer. A study is reported of the effect of background radiation and source scattering on 3 flames, air-propane, air-hydrogen and air-acetylene, and of the effects of variation of fuel gas pressure, zone of measurement in the flame, analysing monochromator slit-width and wavelength of measurement. The air-propane flame appears to offer several advantages. The atomic fluorescence of 10 metals is described; those of Co, Fe and Mn have not been previously reported. Excitation of spectra is achieved by means of an a.c. xenon arc lamp or individual discharge lamps. 相似文献
9.
10.