Uranium determination radiochemical methods

Parsa [228] has described a sequential radiochemical method for the determination of thorium (and uranium) in soils. Mukhtar et al. [229] have described a laser fluorometric method for the determination of thorium (and uranium) in soils. Steam digestion has been employed in the preparation of soil samples for the determination of thorium (and uranium) [230]. Thorium (and uranium) were determined by X-ray fluorescence using a germanium planar detector and by chemometric techniques. No sample preparation was required in this method [231]. 

Parsa [49] has described a sequential radiochemical method for the determination of uranium (and thorium) in soils. 

Radiochemical Methods for Determination of Polonium, Radiolead, Uranium, and Plutonium... 

Skwarzec, B. 1997. Radiochemical methods for the determination of polonium, radiolead, uranium and plutonium in environmental samples. Chem. Anal. (Warsaw) 42 107-115. 

A radiochemical method for the determination of uranlum-237 Is based on complexlng the uranyl Ion In alkaline solution with hydroxylamlne hydrochloride, followed by scavenging with zirconium hydroxide and extraction of the uranium from hydrochloric acid solution with trllsooctylamlne-xylene. The technique has been applied successfully to the determination of uranlum-237 homogeneous reactor fuel solutions. 

There are methods available to quantify the total mass of americium in environmental samples. Mass spectrometric methods provide total mass measurements of americium isotopes (Dacheux and Aupiais 1997, 1998 Halverson 1984 Harvey et al. 1993) however, these detection methods have not gained the same popularity as is found for the radiochemical detection methods. This may relate to the higher purchase price of a MS system, the increased knowledge required to operate the equipment, and the selection by EPA of a-spectrometry for use in its standard analytical methods. Fluorimetric methods, which are commonly used to determine the total mass of uranium and curium in environmental samples, have limited utility to quantify americium, due to the low quantum yield of fluorescence for americium (Thouvenout et al. 1993). 

To illustrate three common radiochemical separation techniques - precipitation, solvent extraction, and cation exchange - in parts 7A, 7B, and 1C. These methods separate thorium from its uranium parent. Radionuclide recovery is measured by comparing count rates to the original sample, not by carrier yield determination. 

C26.05.01 Cl000-90(1995)el Standard Test Method for Radiochemical Determination of Uranium Isotopes in Soil by Alpha Spectrometry... 

The main specifications concern the uranium content in UFg by gravimetric and titrimetric methods, isotopic composition (as listed earlier), el ental impurities by atomic absorption, ICP-AES, spectrographic, colorimetric, titrimetric, spark source mass spectroscopy and radiochemical (alpha and gamma spectrometry and neutron absorption) methods, and organic impurities like hydrocarbons and their derivatives. Modern methods also deploy ICPMS techniques for the determination of impurities and isotopic composition (C1287 2010). It is beyond the scope of this book to present all these methods in detail so a number of examples are shown later. 

C1473, A. (2011). Standard test method for radiochemical determination of uranium isotopes in urine by alpha spectrometry. West Conshohocken, PA ASTM. 

Recent applications of photon activation to the analysis of heavy elements include the determination of Te, Sr, and Pb. Campbell and Steele measured Te in the presence of U by Ge(Li) spectrometry of the activated Te isotope [ Te(y,n) Te] with a half-life of 17 d. The method is useful because it avoids the complications arising in n.a.a. caused by fission of the uranium giving rise to direct and spectral interferences from fission products. The measurement of "Sr induced by Sr(), n) and Sr(y,y ) reactions using 30 MeV Bremsstrahlung has been applied to the analysis of Sr in sea-water at the 8 p.p.m. level this involved a radiochemical separation of the 2—8 h Sr. The (y,n) reaction of Pb has been used for the determination of Pb in milk powder.Measurement of the Pb isotope (/ 52 h) after a non-specific sulphate precipitation of the Pb is sufficient to attain a limit of detection of 0.5 //g. The activity was measured with a NaI(TI) detector after "Sr, which was also produced, had decayed. 

A number of the prooeradiometric determination of wanlum. The method of separation in these procedures, however, is applicable to radiochemical analysis and is, therefore, included. A number of papers and reports describe, in detail, procedures for the determination of uranium. These should be noted. The work of Rodden and Warf has frequently been mentioned in this paper. In addition to procedures for the precipitation, solvent extraction, volatilization, and electrodeposltlon of uranium, these authors have presented a number of selected procedures for the solution of ores and minerals and the separation and determination of uranium. Procedures for the analytical determination in naturally occurring materials have also been described by Hodden and Tregonning,- Grimaldi, May, Fletcher, and Tltcomb, 2Z. Sohoeller and Powell,and in the "Handbook of Chemical Determination of Uranium in Minerals and Ores." 2 The recent publication by Hoore on extraction with amines contains a collection of procedures., many of which have to do with the separation of uranium. 

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