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K. S. Patel N. Agarwal 《International journal of environmental analytical chemistry》2013,93(1-3):63-70
Abstract A new spectrophotometric method is described for the determination of thallium in soil by extraction of Tl(III) with a toluene solution of N,N′-diphenylbenzamidine after acidification with 0.2–4.0 M HCl, and reaction of the extract with Crystal violet in the presence of 0.01–0.8 M HCl. The value of molar absorptivity of Tl(III)-X-CV complex (where X = Cl or Br; CV = Crystal violet) in toluene is 7.00 × 104 1 mole?1 cm?1 at the absorption maximum of 610 nm. The detection limit of the method is 20 ng ml?1. The present method is free from interference of almost metal ions commonly associated with Tl. The method has been applied for analysis of the metal to soils. 相似文献
53.
Dimosthenis L. Giokas Evangelos K. Paleologos Miltiades I. Karayannis 《International journal of environmental analytical chemistry》2013,93(2):167-171
Glossary On Air Pollution, Who Regional Publications European Series No. 9 (Director, Promotion of Environmental Health, WHO Regional Office for Europe, Scherfigsvej 8, DK-2100 Copenhagen θ) 1980, 114 pages (including an introduction, a list of reviewers and a list of the sources of definitions), stiff paper cover, format 239 ± 159 mm, ISBN 92-9020-109-6, WHO Health and Biomedical Information Programme, CH-1211 Geneva 27, SFr. 12. Spektroskopische Methoden in Der Organischen Chemie (in German), by Manfred Hesse, Herbert Meier and Bernd Zeeh, 478 pages, including 169 figures and 86 tables, flexible paper cover, ISBN 3-13-576101-0, Georg Thieme Verlag, Stuttgart 1979, price DM 26.80. Analysis of Polycyclic Aromatic Hydrocarbons in Environmental Samples, World Health Organisation/International Agency for Research on Cancer, IARC Publication No. 29 (Series: Environmental Carcinogens, Selected Methods of Analysis, Volume 3, edited by H. Egan, Laboratory of the Government Chemist, London, U.K. et al.) 1980, 240 pages (including 17 figures, 18 tables, many formulae, an annex with 8 methods of analysis and 29 pages of valuable references in two sections), linen, format 242 ± 186 mm, ISBN 92-8-321129-4, WHO Health and Biomedical Information Programme, CH-1211 Geneva 27, US$30 or SFr. 50. Toxic Metals and Their Analysis by Eleanor Berman, Cook County Hospital, Chicago, Illinois, U.S.A., 304 pages (including an index of 5 pages, 29 tables and 5 figures), linen, format 241 × 163 mm, ISBN 0-85501-468-7, published 1980 by Heyden International Topics in Science, Spectrum House, Hillview Gardens, London NW4 2JQ, U.K., prices £12, US$27 or DM 56. 相似文献
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Erzsébet P. Gere Barna Bérczi Péter Simándi Gyula Wittmann András Dombi 《International journal of environmental analytical chemistry》2013,93(7):443-450
The kinetics of the reactions of H 2 O 2 and of methyl, ethyl, tert -butyl, and cumene hydroperoxides with I m were investigated in the presence and absence of molybdate as catalyst. These results were utilized to develop an analytical method for the simultaneous determination of H 2 O 2 and organic hydroperoxides in aqueous solutions. The total amount of H 2 O 2 and organic hydroperoxides can be determined by the spectrophotometric measurement of $ {\rm I}_3^ - $ formed quantitatively during 30 min of heating at 60°C. Catalase selectively decomposes H 2 O 2 in solutions containing organic hydroperoxides. The total amount of the latter can therefore be determined iodometrically after H 2 O 2 decomposition. In the oxidation of leuco crystal violet to crystal violet by H 2 O 2 and organic hydroperoxides, horseradish peroxidase exerts similar activities in the reactions involving methyl and ethyl hydroperoxides and H 2 O 2 , but its activity is much lower with tert -butyl and cumene hydroperoxide. It was observed that acetate buffer is unsuitable for pH adjustment in this type of hydroperoxide determination in consequence of the slow oxidation of the dye in the blank solution. 相似文献
55.
A simple, rapid, sensitive, and inexpensive method for spectrophotometric determination of chromium(VI), based on the absorbance of its complex with 1,4,8,11-tetraazacyclotetradecane (cyclam) is presented. The complex showed a molar absorbtivity of 1.5?×?104?L?mol?1?cm?1 at 379?nm. Under optimum experimental conditions, a pH of 4.5 and 1.960?×?103?mg?L?1 cyclam were selected, and all measurements were performed 10?min after mixing. Major cations and anions did not show any interference; Beer's law was applicable in the concentration range 0.2–20?mg?L?1 with a detection limit of 0.001?mg?L?1. The standard deviation in the determination is ±0.5?mg?L?1 for a 15.0?mg?L?1 solution (n?=?7). The described method provides a simple and reliable means for determination of Cr(VI) in real samples. 相似文献
56.
Shigeru Masuda 《Applied Surface Science》2010,256(13):4054-4064
A systematic understanding and controlling of gap states formed at the organic-metal interfaces is a key factor for fabricating functional organic-metal systems, as in case of heterojunctions in semiconductor devices. We report here the characterization of gap states near the Fermi level of metal substrate by metastable atom electron spectroscopy and first-principles density functional calculations. The gap states in organic-metal systems are classified into two types, i.e., chemisorption-induced gap states (CIGSs) and complex-based gap states (CBGSs). CIGSs can be further classified whether the metal wave function tails a short distance into the chemisorbed species with the exponential decay (damping type) or is exposed sufficiently to the chemisorbed species by mixing with the organic orbitals (propagating type). CIGSs observed in alkanethiolate and C60 on Pt(1 1 1) are their typical examples, respectively. As a consequence, alkanethiolate serves as a poor mediator of metal wave function, whereas C60 acts as a good mediator, which is responsible for tunneling mechanism and eventually electric conductivity in the relevant metal-organic-metal junctions. CBGSs are identified in bathocuproine films deposited on K-covered Au, where the K atoms migrate into the film to form an organic-metal complex. The CBGSs are distributed over the multilayer film, in contrast to the case of CIGS. With increasing film thickness, the CBGSs exhibit incommensurate energy shifts with the valence band top of the film, indicating that the Schottky-Mott model breaks down as evaluating charge transport in organic-metal systems. 相似文献
57.
探讨了分光光度法测定吸收液中二氧化氮,采用盲样与已知标准样品进行比对,结果表明,该法符合质量控制要求,并对可能影响质控结果的因素进行了讨论。 相似文献
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A new spectrophotometer design permits simultaneous measurement of color and surface appearance attributes of reflecting specimens. The new design provides a multi-channel spectrometer that is simple, compact, light, and inexpensive, while having a unique combination of features and performance. Novel d/8° geometry provides new capabilities. With a single quick measurement, the instrument measures color and several other appearance attributes. A concentric optical configuration used for the spectrometer eliminates third-order optical aberrations. The optical design and unique features are described and performance data are presented. 相似文献