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51.
A flow injection on-line sorption preconcentration method for the electrothermal AAS determination of platinum has been developed. The pyrrolidine dithiocarbamate complexes of either Pt4+ or Pt2+, formed in 0.7 mol L–1 HNO3, are on-line adsorbed on the inner walls of a PTFE knotted reactor and subsequently eluted with methanol. An enhancement factor of 112 and a detection limit (3 σ) of 10 ng L–1 along with a sampling frequency of 21 h–1 are achieved with a 90 s preconcentration time at a sample flow rate of 8.8 mL min–1. The relative standard deviation is 2.5% for 0.4 μg L–1 Pt. The method has been applied to the determination of platinum in blood samples. 相似文献
52.
The anion-exchange enrichment of TlCl(-)(4) coupled to flame AAS is applied to the determination of the total, pseudo-total (not bound in the silicate matrix) and mobile (plant available) content of thallium in soils. Ascorbic acid is used as a new efficient eluent of thallium. The limit of detection of the method is 0.04,mug/g, the relative standard deviation at the 1 mug/g level is about 3%. The method is rapid and simple. 相似文献
53.
M. Katkevics E. Korchagova T. Ivanova V. Slavinska E. Lukevics 《Chemistry of Heterocyclic Compounds》2004,40(6):734-741
New 3-hydroximino-1-hydroxy-2-pyrrolidinones have been synthesized by the interaction of NH2OH and NH2OBn with the methyl esters of 2-oxo-3-butenoic acid derivatives. Some intermediate compounds have been isolated and identified and the reaction mechanism is discussed. 相似文献
54.
G. F. Chernenko K. I. Demenkova E. E. Ivanova É. N. Shmidt 《Chemistry of Natural Compounds》1990,26(5):548-551
A study of the chemical composition of a petroleum ether extract of the bark of Yeddo spruce growing in Khabarovsk Territory has shown that the neutral fraction of the extract contained waxes, glycerides, diterpenoids — epimanool, cis- and trans-abienols, and phyllocladenol, and triterpenoids — the epimeric 3α-and 3β-methoxy-21-hydroxy-Δ14-serratenes and a ketone which has been ascribed the structure of 21-keto-3β-methoxy-Δ14-serratene. 相似文献
55.
Chevela V. V. Bezryadin S. G. Semenov V. E. Shamov G. A. Ivanova V. Yu. 《Russian Journal of Coordination Chemistry》2003,29(6):419-424
The geometric parameters of dl- and d-tetranuclear iron(III) tartrates [Fe4(d-L)2(l-L)2(H2O)8]4–and [Fe4(d-L)4(H2O)8]4–(H4L is tartaric acid) were optimized using the molecular mechanics method (MIND program, Dashevskii–Plyamovatyi model). 相似文献
56.
Wang W Buchholz A Ivanova II Weitkamp J Hunger M 《Chemical communications (Cambridge, England)》2003,(20):2600-2601
A general method for the synthesis of quaternary ammonium cations in acidic zeolites by a direct reaction of tertiary amines and alcohols is described. 相似文献
57.
V. V. Berentsveig Zaki A. Hasan P. B. Fabrichnyi T. M. Ivanova A. P. Rudenko 《Reaction Kinetics and Catalysis Letters》1980,15(2):239-243
The state of mixed iron-tin oxide catalysts with a variable ratio of their metallic components has been studied by Mössbauer and ESCA spectroscopy. The results are compared with the activity of these catalysts in cyclohexane oxidation.
- . .相似文献
58.
V. K. Gryaznov A. N. Ivanova G. L. Gutsev A. A. Levin A. V. Krestinin 《Journal of Structural Chemistry》1989,30(3):469-472
Branch of the Institute of Chemical Physics, Academy of Sciences of the USSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 30, No. 3, pp. 132–134, May–June, 1989. 相似文献
59.
Summary Methyl -nitrocrotonate has been synthesized by the condensation of methyl nitroacetate with acetaldehyde, acetylation of the methyl -nitro--hydroxybutyrate, and subsequent deacetylation of the resulting product. 相似文献
60.