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排序方式: 共有105条查询结果,搜索用时 46 毫秒
1.
Zusammenfassung Auf Grund seiner katalytischen Wirkung auf die Lumineszenzreaktion von Luzigenin mit Wasserstoffperoxid läßt sich Osmiumtetroxid im Konzentrationsbereich von 1 bis 60g/5 ml mit Hilfe der Simultan-komparationsmethode hinreichend genau bestimmen. Die störenden Ionen des Cu, Cd, Pb, Hg, Co, Ni, Ca und Mg lassen sich mit ÄDTA maskieren.
Summary Osmium tetroxide can be detected in the concentration range of 1 to 60g/5 ml through its luminescence reaction with hydrogen peroxide and lucigenin with sufficient precision by means of the simultaneous comparation method. The interfering ions (Cu, Cd, Pb, Hg, Co, Ni, Ca, and Mg) can be masked with EDTA.
Résumé En utilisant l'action catalytique du tétroxyde d'osmium sur la réaction de luminescence de la lucigénine avec l'eau oxygénée, on peut le doser avec suffisamment de précision dans le domaine des concentrations allant de 1 à 60g/5 ml par la méthode de comparaison photométrique. On peut masquer par l'EDTA les ions gênants de Cu, Cd, Pb, Hg, Co, Ni, Ca et Mg.相似文献
2.
I. Sajó und Frau B. Sipos 《Fresenius' Journal of Analytical Chemistry》1966,222(1):23-50
Summary A novel method has been developed for the rapid analysis of silicates. Each component is determined from the temperature variation of the solution resulting from the addition to the test solution of a selectively reacting reagent. By suitable construction of the instrument the concentration of the component to be determined can be read directly in per cent. The determination of a component takes usually 4 to 8 minutes.In the test solution a temperature change proportional to the concentration of the component to be determined has been produced by the following reagents: sulphuric acid for barium, ammonium peroxodisulphate for iron, hydrogen peroxide for titanium, hydrofluoric acid for silicic acid, potassium permanganate for sulphur, ammonium molybdate and hydrogen peroxide for phosphate, potassium permanganate for manganese, potassium oxalate for calcium, diammonium hydrogenphosphate for magnesium, ascorbic acid for chromium. The above components can be determined without any separations. Only in the case of aluminium a separation of silicic acid from aluminium by dehydrating with perchloric acid in necessary. Thereafter the aluminium can be determined with hydrofluoric acid.The precision of the determinations is practically identical with the precision of the usual plant methods. 相似文献
3.
The ionic product of water, pK(w) = - log[H(+)][OH(-)] has been determined in aqueous solutions of tetramethylammonium chloride over the concentration range of 0.1-5.5 M at 25 degrees C using high-precision glass electrode potentiometric titrations. pK(w) data relating to aqueous potassium and sodium chlorides at ionic strengths up to 5 M are markedly lower than the tetramethylammonium chloride results. These differences are almost certainly due to weak associations between potassium and (especially) sodium and hydroxide ions. 相似文献
4.
A protocol has been developed for the reliable titration of aqueous sulfite solutions which minimizes photodecomposition effects.
This procedure has been used to measure the protonation constants of the sulfite ion in aqueous solution by glass electrode
potentiometry at 25.0‡C and ionic strengths (I) from 0.1 to 5.0M in NaCI media and atI = 1.0M in KC1 and Me4NCl media. These measurements provided evidence of weak but significant ionpairing between SO2/3 -and Na+ with a formation constant of logK
Na = 0.431 in 1.0M Me4NCl. This was in very good agreement with the value logK
Na = 0.410 measured directly by Na+ ion-selective electrode potentiometry. Evidence is also presented for an extremely weak association of K+ and SO
2
3
-with logK
k
= 0.22 in 1.0M Me4NCl. 相似文献
5.
Judit Sipos Benjamin Podnyi Istvn Hermecz Levente Pusztay Gbor Tth Lszl Szilgyi 《Journal of heterocyclic chemistry》1989,26(4):1061-1068
Ethyl 4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidine-3-carboxylates 1–4 , their piperidine ring homologues 5–6 and their 2-oxo isomers 7–9 were reacted with benzaldehyde. At low temperature, kinetically stable addition products were formed. Thermodynamically stable condensation products were obtained at higher temperature, which were also formed when the addition products were refluxed in benzene. The 9-benzyl derivatives were prepared by the hydrogenation of the condensation products over Pd/C. The stereochemical features of the new compounds were determined via 1H and 13C nmr chemical shift and coupling constant analysis and NOE measurements. 相似文献
6.
F. Briski S. Cerjan-stefanovic L. Sipos 《International journal of environmental analytical chemistry》2013,93(1-4):137-148
Abstract The removal of ammonia from mineral medium containing known concentrations of ammonia (up to 300 mg/L) and from ground water by biological oxidation was studied. Nitrifying bacteria were isolated from ground water containing ammonia. Ammonium ion was determined by a standard titration technique while nitrite and nitrate ions were determined by ion chromatography (IC Supersep anion column) using 1.5 mM phtalic acid solution containing 5 % acetonitril as eluent. Depending on its concentration in water biooxidation of ammonia lasted from 48 hours till three weeks. 相似文献
7.
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9.
Attila Sipos Antal Udvardy Attila C. Bényei Sándor Berényi 《Central European Journal of Chemistry》2013,11(8):1278-1285
The synthesis of 3-deoxyoripavine (7) was realized as a novel and promising intermediate towards the synthesis of the important class of dopaminergic and/or serotonergic 10-deoxyaporphines and the special pharmacological tool µ opioid antagonist cyprodime. Generally, the preparation of these valuable biologically active compounds was achieved in remarkable yields. 相似文献
10.
Six monoprotected acetals and -thioacetals of glutaradehyde and its symmetrical dimethyl derivatives were synthesized. Microwave-assisted heating proved to be a substantially more selective method for monoprotection than conventional heating. All reactions were efficient and only traces of diprotected material were formed. 相似文献