Sample Preparations and Separations

The procedure for chemical separation of these various aliquots is based on anion exchange 

The swipe is placed in a covered quartz tube and ashed in an oven at 600°C for 8-10 h. A blank swipe and an empty quartz tube are treated at the same time to provide the swipe and process blank values. 

The ash is dissolved in 16 M HNO3 and dried and re-dissolved several times. It is then treated with H2O2 and aqua regia to complete the oxidation and sample destruction process and a mother solution is re-dissolved in 8 M HNO3. 

The mother solution is split into 3 parts 20% will be used for UIDMS and Pu analysis by TIMS, and alpha spectrometry, respectively. Forty percent will be used for U isotopic analysis, and Pu elemental and isotopic analysis by IDMS (there is no un-spiked Pu fraction and Pu isotopic composition will be estimated by isotopic stripping of the Pu spike). The rest (40%) of the solution is kept as an archive. 

High-purity isotopic spikes of (IRMM-057) and Pu (IRMM-044) are added to the 20% and 40% fractions, respectively, and the isotopes are equilibrated by repeated drying and re-dissolution in 16 M HNO3 and treatment with H2O2. 

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Carey et al. 1979 Kadoum 1968). Some problems still exist with sample preparation and separation, which affect the precision, accuracy, and specificity of analyses. Further studies to improve sample preparation and selectivity of detection might be beneficial in improving the reliability of existing methods. 

Multidimensional liquid chromatography encompasses a variety of techniques used for seunple separation, cleanup and trace enrichment [12,279-289]. A characteristic feature of these methods is the use of two or more columns for the separation with either manual or automatic switching by a valve interface of fractions between columns. These techniques require only minor modification to existing equipment, and of equal importance, enable the sample preparation and separation procedures to be completely automated. 

Recently, the focus has been placed especially on the chromatographic interface as a means for improving bioanalytical efficiency and novel advantages on samples preparation (and separation) related to the fact that they are generally the rate limiting steps in drug development process. 

AUTOMATIC SAMPLE-PREPARATION AND SEPARATION TECHNIQUES [CH. 4 Gas Chromatograph Canopy... 

The reader should find it helpful that the most recent published articles of the last few years are discussed. As in the first edition, special attention is paid to reversed-phase separations without neglecting other HPLC techniques. Specialists describe in detail, step by step, sample preparation and separation conditions. The applications to food chemistry are specific and practical. The book will once again find a large audience in the fields of chromatography, analytical chemistry, and, especially, food chemistry and food technology. 

Laboratory robotics represents an attractive approach for the automation of sample preparation and separation steps in radiochemical analysis, and for many years, such methods have been routinely used by laboratories serving the analytical needs of the International Atomic Energy Association.64 68-72 However, there are currently a limited number of published studies containing technical details on the radiochemical separations and how they were automated. Accordingly, the remainder of this chapter will focus on fluidic approaches. 

It is interesting that, in analytical chemistry, besides the efforts to increase the sample throughput and to decrease the detection limits, another trend can be observed which is directed to the analysis of more and more complex mixtures without laborious sample preparation and separation steps. This development was triggered by the requirements of bio- and environmental analysis and is closely connected to the development of multidimensional analytical methods, as well as hyphenated techniques which provide much more selectivity than one-dimensional analytical methods. Among the range of hyphenated techniques, those which combine a high separation efficiency with a maximum of structural information are of particular importance. These are hyphenated techniques such as GC-MS, LC-MS, LC-NMR and LC-NMR-MS. 

Haddad, P.R. Dohle, P. Macka, M. Developments in 38. sample preparation and separation techniques for the determination of inorganic ions by ion chromatography... 

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