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A simple and sensitive method for separation and quantitative determination of antidiabetic drugs in pharmaceutical preparations has been established and validated. Commercial formulations of five antidiabetic drugs (metformin, pioglitazone, rosiglitazone, glibenclamide, and gliclazide) were chosen for the studies. The compounds were extracted, isolated, purified, recrystallized, and characterized by measurement of melting point, λ max , and IR. Quantitative determination was performed by HPLC, TLC, and column chromatography supplemented with UV spectrophotometry. Two of the combinations, metformin + pioglitazone and metformin + gliclazide, were separated by open-column chromatography. Detection was by UV spectrophotometry in HPLC and by use of iodine vapor in TLC.

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3-Mercapto-5-(2′-hydroxynaphthylazo-1′)-1,2,4-triazole (metrian); 3-mercapto-5-(3′,4′-dihydroxyphenylazo-1′)-1,2,4-triazole (metriap); 3-mercapto-5-(2′,4′-dihydroxy-3′-carboxyphenylazo-1′)-1,2,4-triazole (metriarez-γ), and 2-mercapto-5-(2′,4′-dihydroxy-5′-carboxyphenylazo-1′)-1,3,4-thiadiazole (metidarez-β) have been used to determine, by different methods, milligram quantities of Fe(II) and Zn(II), present together in pharmaceutical preparations, both multivitamin preparations and preparations containing microelements. Results from ion chromatography (IC) were compared with those from classical spectrophotometry (D 0 ), derivative spectrophotometry (D 1 and D 2 ), and atomic absorption spectrometric (AAS). Results were analyzed statistically and compared with the declared amount. The advantages of the proposed method for determination of Fe(II) and Zn(II) include its excellent precision and the reproducibility of the results.

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During nuclear fuel reprocessing, monitoring of U and Pu concentration in every stage is very essential for process control purpose. A simple and fast spectrophotometric method for a simultaneous estimation of U and Pu in Plutonium Uranium Recovery by Extraction (PUREX) process’s tail end stream like Pu product where Pu concentration is much richer than that of U is described here. The method involves reduction of the bulk amount of Pu to Pu(III) using ascorbic acid in 1 M HNO3. Visible absorption peaks were measured at 416 nm for U and at 600 nm for Pu using a fiber optic probe of path length 40 mm. The methodology enables quantification of U and Pu concentration in the Pu product samples with a precision of 2.8 and 2.1%, respectively.

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A new spray reagent has been used for TLC detection and spectrophotometric quantification of dichlorvos after extraction with ethanol from bluish tinged maize grains. Silica gel G as stationary phase with cyclohexane-acetone-methanol 8:3:0.5 (ν/ν) as mobile phase was identified as the best TLC system for detection and migration (R F) of dichlorvos. On alkaline hydrolysis dichlorvos forms dimethylphosphoric acid and dichloroacetaldehyde; the latter reacts with 2-thiobarbituric acid to give a sharp pink spot. The reagent is selective for dichlorvos, and does not react with other organophosphorus, organochlorine, carbamate, and synthetic pyrethroid insecticides. The constituents of viscera (amino acids, peptides, proteins, etc.) and grain do not interfere with the test. The lower limit of detection on silica TLC plates was 18 μg. The absorbance maximum (λ max) of the pink color formed by dichlorvos was 500 nm. A plot of absorbance against concentration was a straight line passing through the origin and obeying the Beer-Lambert law in the concentration range 50–350 μg mL−1. The method has been used for identification of dichlorvos in cereals, pulses, vegetables, and fruit.

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Tea is one of the most popular beverages in the world. The exact composition of tea depends on the manufacturing process. Our goal was to optimize the chromatographic conditions for separation of tea extract and to apply the optimized method for determination of gallic acid in oolong, black, and pu-erh tea. Chromatographic separation was performed on silica gel 60 F 254 TLC plates with chloroform-ethyl acetate-formic acid, 5 + 4 + 1 ( v/v ), as mobile phase. Densitometric measurement was performed in the ultraviolet region at λ = 280 nm. Quantification of gallic acid in pu-erh tea was also performed by a spectrophotometric method based on the coupled redox complexation reaction occurring in the system Fe(III)-gallic acid-2,2′-dipyridyl ( λ max = 522 nm).

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The kinetic method developed allowed us to analyse of two-component actinide mixtures without separation. The concentration changes in the system where complex dissociation reaction takes place were determined by spectrophotometry.

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A method for the dissolution of sintered UO2 samples and the determination of ammonium ions in the solution by spectrophotometry for the chemical quality control of UO2 fuel for nitrogen is described. The acid mixture used simplifies the problem of recovery of uranium from the waste generated during the analysis of nitrogen. Nitrogen content in ppm in the sintered UO2 samples is determined within an RSD of 10%.

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To achieve end user’s specified PuO2, controlling and monitoring of Pu in its fourth valency state is essential prior to the conversion of Pu-nitrate to its oxide through oxalate precipitation process. Conventional radiometric procedure for the analysis of Pu oxidation state in Pu-nitrate solution containing trace level of Pu(III) has limitation due to oxidation of Pu(III) during the sample preparation with respect to acidity. A simple direct spectrophotometry using an optic fiber spectrophotometer was attempted for the estimation of trace level of Pu(III), after separating the bulk amount of Pu(IV) by maintaining the sample acidity. By using a synergistic mixture of 30 % TBP and 1 M theonyl trifluoro acetone in benzene, the Pu(IV) could be removed to a level which doesn’t interfere in the Pu(III) absorption.

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The extractive properties of the ortho-aminophenol reagent upon U(VI) were investigated in two solvents: 4-chlor-acetophenone and acetylacetone, in a water-organic solvent system. The method here proposed is based on the complexation reaction of the uranyl ion, UO2 2+, with ortho-aminophenol dissolved in 4-chlor-acetophenone, at room temperature, over a pH interval = 4–6, followed by spectro-photometry of the organic phase, involving measuring of absorbancy at 569.6 nm. The Beer law is valid over the 1–12 μg U(VI)/mL concentration interval, with molar absorbtivity εmax = 4.3 × 105 mol−1 cm2 and Sandell sensitivity = 0.0526 μg cm−2. The structure, stability and solubility of the formed complex was studied by UV–VIS and IR spectrometry, diffractometry and scanning electron microscopy. The mixed complex formed between the uranyl ion and the ortho-aminophenol dissolved in 4-chlor-acetophenone, [UO2.(L)2.(S)4], is characterized by the following parameters: metal/ligand combination ratio: M/L = 1/2, stability constant β = 2.06 × 106, distribution coefficient D = 66.56 (Vorg = Vaq), percentage extraction E% = 98.52, and recovery factor, R%, ranging between 99.48 and 99.85%.

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Abstract  

The method of differential spectrophotometry with the use of Arsenazo III for uranium determination with masking Zr and Pu by 1,2-diaminecyclohexanetetraacetic acid in acetate buffer and carboxyarsenazo for determination of plutonium without its separation from uranium is applied for analysis of the spent fuel of VVER type reactors.

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