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Abstract  

The isotope dilution method, which is based on the isolation of a constant substoichiometric amount, can be completed by a group of radiometric techniques in which this amount is a function of the concentration to be determined. It is convenient then to plot the experimental data in such a way that a straight line is obtained. The methods which can be used in the application of this principle are discussed, mathematically treated and compared to the original procedure of RŮZIČKA and STARÝ. Expressions are derived for the relative statistical error and the limit of detection.

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Abstract  

Enthalpies of solution and dilution of aqueous solutions of sodium diclofenac salt were measured by isoperibolic calorimeter at 293.15, 298.15, 303.15, 308.15 and 318.15 K. The concentration of the electrolyte was restricted to solubility salt at various temperatures and did not exceed 0.035–0.057 mol kg−1 values depending on the studied temperature. The virial coefficients were derived from Pitzer’s model and the excess thermodynamic functions of both the solution and the components of the solution were calculated. The analysis of thermodynamic characteristics of the solution from concentration and temperatures was carried out and discussed.

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Abstract  

Isotopic dilution is shown to be a suitable method for the analysis of traces of Lebaycid in oranges with appropriate sensitivity, accuracy and precision. The procedure involves solubilization of Lebaycid in acetonitrile followed by purification: extraction with hexane from a mixture of methanol and water, chromatography in an alumina column and TLC on silica gel. Factors governing precision are discussed.

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Abstract  

The use of isotope dilution technique to eliminate problems associated with demands for a high load capacity in column-coupling capillary isotachophoresis was studied. Determinations of phosphate present in a model mixture and in white wine served for the evaluation of this approach to quantitative analysis in isotachophoresis. A high selectivity of the analysis with acceptable accuracy and precision of the determination also in complex ionic mixtures in a short time are obvious advantages of this approach.

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Redox substoichiometry in isotope dilution analysis

II. Determination of antimony content in metallic zinc

Journal of Radioanalytical and Nuclear Chemistry
Authors: T. Kambara, J. Suzuki, H. Yoshioka, and N. Nakajima

Abstract  

Isotope dilution analysis using the redox substoichiometric principle has been applied to the determination of antimony content in metallic zinc. As the substoichiometric reaction, the oxidation of trivalent to pentavalent antimony with potassium permanganate was used, followed by separation of these species by the BPHA extraction of trivalent antimony. Determination of antimony contents less than 0.5 μg was found to be possible with good accuracy, without separation of zinc ions. The antimony content in metallic zinc was determined to be 19.7±0.8 ppm, in good agreement with the results obtained by the other analytical methods.

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Redox substoichiometry in isotope dilution analysis

IV. Determination of antimony content in metallic tin

Journal of Radioanalytical and Nuclear Chemistry
Authors: T. Kambara, J. Suzuki, H. Yoshioka, and Y. Ugai

Abstract  

The oxidation reaction of antimony(III) with potassium dichromate has been investigated radiometrically. The quantitative oxidation of antimony(III) was found to be not disturbed even in large amounts of tin(IV). On the basis of these results the redox substoichiometric isotope dilution analysis using potassium dichromate as the oxidizing agent was proposed for the determination of antimony in metallic tin. The antimony content of 1.22±0.05 μg in metallic tin (10 mg) was determined without separation of the matrix element.

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Redox substoichiometry in isotope dilution analysis

V. The use of potassium bromate as the oxidizing agent in the analysis of metallic zinc for antimony

Journal of Radioanalytical and Nuclear Chemistry
Authors: T. Kambara, J. Suzuki, H. Yoshioka, and Y. Watanabe

Abstract  

Radiometric titration of antimony(III) with potassium bromate in hydrochloric acid media using the standard series method provided much valuable informations on the titration errors which depended on the concentrations of the acid and antimony(III). The hydrochloric acid concentrations between 2.5 and 3.0M were found to be optimum for the oxidation of antimony(III) amounts of 4 μg or less. Under these optimum reaction conditions the redox substoichiometric isotope dilution analysis was applied to the determination of antimony in metallic zinc and the satisfactory results were obtained, without the separation of matrix element. Also, the merits of various oxidizing agents hitherto studied for the quantitative oxidation of antimony(III) were compared and discussed.

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detect acrylamide in water [ 25 ], but not used in the detection of CAP. In this study, an evaporation preparative step method with isotope dilution UHPLC–MS/MS has been developed for the determination of CAP in drinking water from Shannan region

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Abstract  

The determination of 9-α-fluoro-16-α-methylprednisolone (dexamethasone) in drugs using isotope dilution method is described. Dexamethasone is tritiated with tritium-labelled acetic acid and in the course of the isotopic dilution the activity of tritium is measured with a liquid scintillator.

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Abstract  

The infinite dilution resonance integrals of fifteen (n,γ)reactions leading to the production of short-lived radioisotopes were determined. The irradiation parameters were checked by comparing the results of different methods and the measuring equipment was carefully controlled.

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