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Abstract  

Pyrohydrolysis is a fast, reliable and convenient method for the decomposition of solid refractory samples. Thoria based mixed oxide nuclear fuels requires more than 1,200 °C reaction temperature to lose its structural integrity so as to release the halides. In the present paper, we report WO3 accelerated pyrohydrolytic extraction technique for the separation of F and Cl from thoria based fuels along with the feasibility of using MoO3 and V2O5. The mechanism of extraction has been investigated in detail using X-ray diffraction and recovery studies. ThO2 along with its halides undergo high temperature solid state reaction with WO3 forming Th(WO4)2 and releasing the halides for their subsequent hydrolysis. The quantification was carried out by ion chromatography with suppressed ion conductivity detection. The average recoveries of the spiked samples for F and Cl were 93–99%. The method was successfully applied for simultaneous determination of F and Cl in thorium based nuclear fuel samples at 950 °C.

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.H. ( 2005 ): Practical ion chromatography , Metrohm, Switzerland. p. 62 . E PSTEIN , E. & B LOOM , A.J. ( 2005 ): Mineral nutrition of plants: principles and perspectives . 2 nd

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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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. Michalski , R. ( 2010 ): Food analysis: Ion chromatography . -in: Cazes , J. (Ed.) Encyclopedia of chromatography Taylor & Francis , CRC Press , Boca Raton, FL. USA . pp. 909 – 912

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Abstract  

An ion chromatographic method has been developed for the determination of traces of Li+, Na+, K+, Ca2+, Mg2+, Sr2+, Fe3+, Cu2+, Ni2+, Co2+, Zn2+, Cd2+, Mn2+ in UO2, ThO2 powders and sintered (Th,U)O2 pellets. This new method utilizes poly-(butadiene-maleic acid) (PBDMA) coated silica cation exchange column and mixed functionality column of anion and cation exchange to achieve the separation of alkali, alkaline earths and transition metal ions, respectively. It involves matrix separation after sample dissolution by solvent extraction with TBP (tri butyl phosphate)-TOPO (tri octyl phosphine oxide)/CCl4. Interference of transition metal ions in the determination of alkali, alkaline earth metal ions are removed by using pyridine 2,6-dicarboxylic acid (PDCA) in the tartaric acid mobile phase. Mobile phase composition is optimized for the base line separation of alkali, alkaline earth and transition metal ions. Linear calibration graphs in the range 0.01–20 μg mL−1 were obtained with regression coefficients better than 0.999. The respective relative standard deviations were also determined. Recoveries of the spiked samples are within ±10% of the expected value. The developed method is authenticated by comparison with certified standards of UO2 and ThO2 powders.

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Abstract  

In the present exploratory study, the applicability of anionic impurities for attributing nuclear material to a certain chemical process or origin has been investigated. Anions (e.g., nitrate, sulphate, fluoride, chloride) originate from acids or salt solutions that are used for processing of solutions containing uranium or plutonium. The study focuses on uranium ore concentrates (“yellow cakes”) originating from different mines. Uranium is mined from different types of ore body and depending on the type of rock, different chemical processes for leaching, dissolving and precipitating the uranium need to be applied. Consequently, the anionic patterns observed in the products of these processes (the “ore concentrates”) are different. The concentrations of different anionic species were measured by ion chromatography using conductivity detection. The results show clear differences of anion concentrations and patterns between samples from different uranium mines. Besides this, differences between sampling campaigns in a same mine were also observed indicating that the uranium ore is not homogeneous in a mine. These within-mine variations, however, were smaller than the between-mine variations.

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Ion chromatography of inorganic cations using a phosphate-coated zirconia stationary phase (PZ) was first attempted. The retentions of cations to PZ increased by elevating the column temperature and the reproducibility of the separation could improve at the higher temperature. The PZ functioned as a cation-exchanger from changes in the retention factor of cations as a function of eluent pH. Furthermore, the Gibbs free energies of cations were estimated from enthalpy and entropy using the retention factors of cations as a function of the column temperature. The reaction was based on the endothermic reaction.

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Abstract  

Dibutyl-and monobutylphosphoric acid in acidic toluene medium were determined by ion chromatography. The procedure involved stripping with dilute sodium hydroxide solution and used carbon tetrachloride as diluent, then detection with a conductivity meter. The effect of flow rate, eluent strength and stripping solution, the effect of chloride and nitrate ion on DBP, the effect on DBP in sodium hydroxide solution, and the effect of organic aliphatic acids were discussed. The detection limits of 0.19 ppm and 0.14 ppm were found for DBP and MBP, respectively.

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Summary  

A technique is presented for the relatively rapid measurement of actinide and beta-emitting radionuclides in waste streams and environmental samples. It uses ion chromatography for elemental selectivity and flow-through scintillation counting with dual parameter pulse-height and pulse-shape analysis for alpha/beta detection and discrimination. The system was tested for one surrogate sample (spiked groundwater from the southeastern U.S.) and two actual samples from the Savannah River Site (supernatant from a highactivity drain tank and sludge from a high level waste tank). For the spiked groundwater, recoveries were quantitative for all of the analytes (americium, curium, plutonium, and strontium) except uranium. For the actual samples, which contained americium, curium, plutonium, strontium, and cesium, the results using the system were within 20% of those obtained independently. Based on these tests, it is concluded that the system is capable of analyzing alpha- and beta-emitting radionuclides in samples that are representative of those encountered at contaminated former weapons sites.

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Abstract  

An on-line method developed for separating plutonium and americium was developed. The method is based on the use of HPLC pump with three analytical chromatographic columns. Plutonium is reduced throughout the procedure to trivalent oxidation state, and is recovered in the various separation steps together with americium. Light lanthanides and trivalent actinides are separated with TEVA resin in thiocyanate/formic acid media. Trivalent plutonium and americium are pre-concentrated in a TCC-II cation-exchange column, after which the separation is performed in CS5A ion chromatography column by using two different eluents. Pu(III) is eluted with a dipicolinic acid eluent, and Am(III) with oxalic acid eluent. Radiochemical and chemical purity of the eluted plutonium and americium fractions were ensured with alpha-spectrometry.

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