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Abstract  

A simple separation method has been developed for thorium(IV) using poly-(dibenzo-18-crown-6) and column chromatography. The separation was carried out from ascorbic acid medium. The adsorption of thorium(IV) was quantitative from 0.001-0.01M ascorbic acid. The elution of thorium(IV) was quantitative with 4.0-8.0M HCl, 3.0-6.0M HClO4, 4.0-8.0M H2SO4 and 1.0-8.0M HBr. The capacity of poly-(dibenzo-18-crown-6) for thorium(IV) was found to be 1.379±0.01 m.mol/g of crown polymer. Thorium(IV) was separated from a number of cations in binary as well as in multicomponent mixtures. The method was extended to the determination of thorium in monazite sand. It is possible to separate and determine 5 ppm of thorium(IV) by this method. The method is very simple, rapid, selective and has good reproducibility (approximately ±2%).

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Abstract  

A simple column chromatographic method has been developed for the separation of thorium(IV) from associated elements using poly-(dibenzo-18-crown-6). The separations are carried out from picric acid medium. The adsorption of thorium(IV) was quantitative from 0.0005–0.05M picric acid. Amongst the various eluents tested, 2.0–8.0M HCl, HBr, 1.0–6.0M HClO4 and 5.0M acetic acid were found to be particularly efficient for the quantitative elution of thorium(IV). The capacity of poly-(dibenzo-18-crown-6) for thorium(IV) was found to be 1.29±0.01 mmol/g of crown polymer. Thorium(IV) was separated from a number of cations in binary mixtures in which most of the cations showed a very high tolerance limit. It was possible to separate thorium(IV) from a number of cations such as lanthanum(III), yttrium(III), uranium(VI), beryllium(II) and barium(II) in multicomponent mixtures. The method was extended to the determination of thorium in monazite sand. It is possible to separate and determine 5 ppm of thorium(IV) by this method. The method is very simple, rapid, selective and has good reproducibility (approximately ±2%).

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Abstract  

Among the separation methods of molybdenum from uranium, the difference in volatility of their chlorides at relatively high temperatures could also be conveniently exploited. This concept is adopted to have a standardization of a method for providing abundant quantity, with a high chemical purity of 99Mo, which is an important radioisotope used in the nuclear medicine. The approach to the standardization consists of identifying the necessary parameters to work at high temperatures and efficient collection of molybdenum. These operations are designed to be carried out in a well ventilated lead-shielded plant with remote facilities.

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Abstract  

In the first part of the paper, we had presented data on simulated conditions favorable for the separation of molybdenum from uranium under conditions existing in irradiated uranium. As mentioned, the aim of this study is the adoption of a method for the routine extraction of 99Mo (fission molybdenum) from the large bulk of uranium and host of radionuclides, additional parameters need to be evaluated to arrive at an effective procedure. This paper deals with the further purification of 99Mo obtained using differential volatility of their chlorides to a quality meeting the requirements of pharmaceutical standards.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: S. Hasilkar, N. Khedekar, Keshav Chander, A. Jadhav, and H. Jain

Abstract  

Studies have been carried out on the solubility of Pu(III) oxalate by precipitation of Pu(III) oxalate from varying concentrations of HNO3/HCl (0.5–2.0M) solutions and also by equilibrating freshly prepared Pu(III) oxalate with solutions containing varying concentrations of HNO3/HCl, oxalic acid and ascorbic acid. Pu(III) solutions in HNO3 and HCl media were prepared by reduction of Pu(IV) with ascorbic acid. 0.01–0.10M ascorbic acid concentration in the aqueous solution was maintained as holding reductant. The solubility of Pu(III) oxalate was found to be a minimum in 0.5M–1M HNO3/HCl solutions containing 0.05M ascorbic acid and 0.2M excess oxalic acid in the supernatant.

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Abstract  

A method for the sequential determination of thorium and uranium has been developed. In the sample solution containing thorium and uranium, thorium is first determined by complexometric titration with ethylenediaminetetraacetic acid (EDTA) and then in the same solution uranium is determined by redox titration employing potentiometry. As EDTA interferes in uranium determination giving positive bias, it is destroyed by fuming with HClO4 prior to the determination of uranium. A precision and accuracy of better than ±0.15% is obtained for thorium at 10mg level and uranium ranging from 5 mg to 20 mg in the aliquot.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: S. Hasilkar, N. Khedekar, Keshav Chander, A. Jadhav, and H. Jain
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Abstract  

The extraction of Am(III), Pu(IV) and U(VI) as representatives of tri-, tetra- and hexavalent actinides by dibutyl-N,N-diethylcarbamoylmethylenephosphonate (DBDECMP) from nitric acid solution has ben studied with an objective of understanding the extraction mechanism. The dependence of the distribution ratios of the actinide ions was studied as a function of the concentration of H+, DBDECMP and NO 3 . The extraction data revealed that all the three actinide ions are extracted as their neutral nitrate complexes solvated by DBDECMP which behaves as neutral extractant only. The absorption spectra of DBDECMP and TBP extracts of these actinide ions were recorded. From the close similarity of these spectra it is inferred that DBDECMP acts as a monodentate extractant in the present system.

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Summary

In this paper we describe a simple, precise, and accurate HPTLC method for quantification of lupeol in the bark of Mimosoups elengi (ME). The bark was extracted with hot methanol in a Soxhlet apparatus. Chromatographic separation of the extract was performed on aluminum foil plates coated with silica gel 60 F254 as the stationary phase. The mobile phase was toluene-ethyl acetate-formic acid 12:2:1 (υ/υ). Densitometric evaluation of the separated zones was performed at 220 nm. The lupeol was satisfactorily resolved at R F 0.64 ± 0.02. The accuracy and reliability of the method were assessed by evaluation of linearity (1000–4000 ng per band), precision (method and instrumental precision, as RSD, 1.06 and 1.03%, respectively), accuracy (97.28 ± 0.89), and specificity in accordance with ICH guidelines.

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Abstract  

Extraction of trivalent (Pu3+, Am3+, actinides and Eu3+, a representative of lanthanides) and tetravalent (Np4+ and Pu4+) actinides has been studied with dihexyl N,N-di-ethylcarbamoylmethyl phosphonate (DHDECMP) in combination with TBP in benzene from 2M nitric acid. The stoichiometries of the species extracted were found to be M(NO3)3·(3–n) TBP·n DHDECMP (for trivalent ions) and M(NO3)4·(2–n) TBP·n DHDECMP (for tetravalent ions) by the slope ratio method. The extraction constants evaluated (from the distribution data) indicate that for tetravalent ions (with solvation number two) the extraction constant increases when TBP (Kh=0.17) molecules are successively replaced by more basic DHDECMP (Kh=0.34) molecules. However, for trivalent ions (with solvation number three) when TBP molecules are totally replaced by DHDECMP molecules stereochemical factors appear and instead of increase, a substantial decrease in extraction constants is observed for Eu3+ and Am3+, a lesser decrease being observed for Pu3+ (larger ion).

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