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941.
P. Quevauviller M. Lachica E. Barahona A. Gomez G. Rauret A. Ure H. Muntau 《Fresenius' Journal of Analytical Chemistry》1998,360(5):505-511
Single extraction tests are commonly used to study the eco-toxicity and mobility of metals in soils, e.g. to assess the bioavailable
metal fraction (and thus to estimate the related phyto-toxic and nutritional deficiency effects) and the environmentally accessible
trace metals upon disposal of e.g. sediment on to a soil (e.g. contamination of ground waters). However, the lack of uniformity
in the different procedures does not allow the results to be compared worldwide nor the procedures to be validated. This paper
describes the interlaboratory testing of EDTA- and DTPA-extraction procedures for soil analysis, followed by the preparation
of a calcareous soil reference material (CRM 600), the homogeneity and stability studies and the analytical work performed
for the certification of the EDTA- and DTPA- extractable contents of some trace metals (following the standardized extraction
procedures).
Received: 21 May 1997 / Revised: 4 July 1997 / Accepted: 9 July 1997 相似文献
942.
S. J. Parry B. A. Bennett R. Benzing A. E. Lally 《Journal of Radioanalytical and Nuclear Chemistry》1997,219(2):191-196
Radiochemical techniques play an important role in nuclear waste management studies at the Centre for Analytical Research in the Environment. Current research includes the measurement of atmospheric emissions from a reprocessing plant, modelling of environmental pathways, and evaluation of reactor materials for the prediction of releases from ultimate disposal sites. A radiochemical separation procedure has been developed for129I, which has been applied to a study of emissions from the Sellafield nuclear reprocessing plant. Atmospheric emissions, rainfall, grass, milk and wild food are analysed to model the ultimate fate of129I. A new procedure has been developed for measuring sub-ppm concentrations of chlorine in archive steel samples as part of programme to produce an inventory of arisings of36Cl from nuclear power stations. The method has been extended to other reactor materials and this paper describes the application of the radiochemical method for Magnox alloys, mild steel and cast iron. 相似文献
943.
L. Ya. Zakharova S. B. Fedorov L. A. Kudryavtseva V. A. Bel'skii A. B. Mirgorodskaya B. E. Ivanov 《Russian Chemical Bulletin》1990,39(8):1555-1559
The hydrolysis of bis(chloromethyl)phosphonic acid p-nitroanilide has been studied in the pH range 6.86–13.0 and the effects of ionic surfactant micelles on this process have also been examined. The nature of the micellar effects of cetyltrimethylammonium bromide (CTAB) and sodium dodecylsulfate (SDS) on this reaction lead us to conclude that both the neutral and anionic forms of the substrate are reactive, and that in the range of pH > pKa hydrolysis of the ionic form of the anilide predominates, while at pH < pKa the reaction of the neutral form is predominant. The binding constants for both the neutral and anionic forms of bis(chloromethyl)phosphonic acid p-nitroanilide in micellar CTAB and SDS solutions have been determined using a kinetic method, as well as by measuring the changes in the acid-base properties of the substrate resulting from the influence of micelles.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1718–1722, August, 1990. 相似文献
944.
A. J. Blotcky E. P. Rack R. R. Recker J. A. Leffler S. Teitelbaum 《Journal of Radioanalytical and Nuclear Chemistry》1978,43(2):381-388
A destructive neutron activation analysis procedure was developed for determining trace aluminum content in bone. It was found
that soil contamination can influence the aluninum bone levels in prehistoric bone specimens. These maximum aluninum content
values for prehistoric bone are larger than those of modern bone and comparable to aluminum levels present in bone from renal
patients. 相似文献
945.
A method that utilizes the Vilsmeier reaction to form a pyrrole ring was developed for the preparation of the previously unknown 7-formyl-2-methyl-4-oxo-3,4-dihydropyrrolo[3,2-d]pyrimidine from 2,6-dimethyl-5-amino-4-oxo-3,4-dihydropyrimidine. The nitrile, which was converted to the amide, was obtained from the oxime of the synthesized aldehyde. 7-Unsubstituted pyrrolopyrimidine was synthesized by oxidation of the aldehyde to the corresponding acid and subsequent decarboxylation. The IR and PMR spectroscopic data are presented.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1672–1674, December, 1977. 相似文献
946.
947.
A three-step synthesis of bispidine ( 1 ) is described. Mannich condensation of N-benzyl-4-piperidone, formaldehyde, and benzylamine afforded N,N′-dibenzylbispidinone ( 5 ), which was reduced under modified Wolff-Kishner conditions to yield N,N′ -dibenzylbispidine ( 6 ). Catalytic debenzylation of this compound gave 1 . 相似文献
948.
E. M. Essassi J. P. Lavergne Ph. Viallefont J. Daunis 《Journal of heterocyclic chemistry》1975,12(4):661-663
The condensation of 3,4-diamino 1,2,4-triazole with ethyl aceloacelate gave 6-methyl-8,9-dihydro(7H)-s-triazolo[4,3-b]-1,2,4-triazepin-8-one ( 2 ); 2 has been caracterized by nmr spectroscopy and by comparison with its methylated derivative prepared in an unambigous manner. 相似文献
949.
950.
A. V. Zaikina E. I. Yarmukhamedova Yu. I. Puzin A. A. Fatykhov Yu. B. Monakov 《Polymer Science Series A》2006,48(5):457-461
The specific features of free-radical polymerization of methyl methacrylate in the presence of a new initiating system, benzoyl peroxide-N,N-dimethyl-N-(methylferrocenyl)amine, are studied. Mutual influence of the ferrocene and amino groups on the kinetic parameters of polymerization and on the microstructure of the resulting polymers is revealed. The polymer formed in the presence of this initiating system is shown to have a predominantly syndiotactic structure. 相似文献