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Abstract  

The basic principles and specific techniques of rapid, automated radiochemical separation techniques that use batchwize separation methods are reviewed.

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) Paracetamol (b) Pseudoephedrine HCl (c) Chlorpheniramine maleate Separation techniques that rely on the property of differential migration play a great role in pharmaceutical formulations analysis. Various

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Abstract  

The chemical separation techniques used at the Dow Chemical Co. are discussed.

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Abstract  

A comparison of two group separation techniques using either NaI(Tl) or Ge(Li) spectrometry is presented for trace element determination in biological materials by neutron activation analysis. The capabilities of both procedures are described in terms of detection limits, precision and accuracy for the determination of the elements As, Cd, Co, Cr, Cu, Fe, Hg, Mo, Ni, Sb, Se, Sn, and Zn in various types of biological samples. For this purpose the (standard) reference materials NBS SRM-1577 Bovine Liver, Bowen's Kale, IAEA Pig Kidney H-7 and IAEA Milk Powder A-11 were analyzed. An attempt was also made to minimize blank values for several elements.

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Much effort has been devoted to improving the capability of separation techniques. The lower the separation volume and the higher the plate number the better the separation. HPLC, UHPLC, CE, and shear-driven chromatography have different separation characteristics. It is shown how the kinetic plot method, originally developed for pressure-driven LC, can be extended to electrically-driven and shear-driven LC. With this extension, the separation speed of pressure-driven, electrically driven, and shear-driven LC can now be compared on a universal basis, i.e. by comparing the separation efficiency or resolution that can be obtained in a given time. As an illustrative example, the separation of coumarin dyes is considered.

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Abstract  

The compositional changes of inorganic elements on freshwater leaching of 35 species of Chinese algae were studied by the determination of the element contents in marine algae using instrumental neutron activation analysis. It was found that alkali metals and chlorine mainly exist as ions in algae, in which, water-soluble K and Na exist as chlorides. While, other elements exist as the states of both ions and organic combination in which the water leaching ratios of alkaline earth metals are the lowest. The combination of trace elements with various organic macromolecules inSargassum kjellmanianum was also studied using neutron activation analysis combined with chemical and biochemical separation techniques. The results indicate that the concentration of many trace elements, such as Zn, Fe, Sc, Th are earths in protein are quite high, and some trace elements can also be combined by pigment and polyphenol. Alkaline earth metal mainly bind with alginic acid inSargassum kjellmanianum.

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Abstract  

After summarising the techniques available generally in analytical chemistry for the separation and pre-concentration of trace elements, reasons are given why some of these procedures have achieved greater prominence in particular radiochemical separations. Examples of contemporary practice and current trends in a wide variety of radiochemical separation problems are then illustrated by reference to papers that have appeared in recent literature.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
G. Klunder
,
J. Andrews
,
M. Church
,
J. Spear
,
R. Russo
,
P. Grant
, and
B. Andresen

Abstract  

Capillary electrophoresis has been used to separate metal ions characteristically associated with nuclear fission. Electrokinetic injections and transient isotachophoretic techniques were employed to increase sample loading and provide on-column concentration of the analyte. On-line concentration factors of approximately 700-fold have been achieved. Indirect-UV absorbance, on-line radioactivity, and indirect laser-induced fluorescence detection were used to monitor analytes of interest. The radioactivity detector consists of a plastic scintillator and photomultiplier tube with a 4π detection geometry. The efficiency was determined to be approximately 80%, enabling samples resident in the detector window for 0.1 minutes to be reliably assayed. Detection of152Eu and137Cs was achieved at the low nCi level. Indirect fluorescence was performed with quinine sulfate as the background fluorophor with α-hydroxysobutyric acid added as a complexing agent. An argon ion laser was used as the excitation source with a diode array detector. Limits of detection for La3+, Ce3+, Pr3+, Nd3+, Sm3+, and Eu3+ were determined to be in the sub — 10 ppb range (6–11 nM) with indirect laser-induced fluorescence detection.

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Abstract  

Radiochemical separation methods have been applied for the neutron activation analysis of impurities in four high-purity refractory metals, Ta, Nb, W and Mo. Impurities in the metals of Ta, Nb and W can be separated into groups using anion exchange resin with HF and/or a mixture of HF acid and HCl, but those in Mo is done using both anion and cation exchange resins. The coprecipitation of U with Th in HF media is also investigated.

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Chromatographic processes are based on an adsorption-desorption mechanism. By this mechanism the sample is distributed between the porous medium and the mobile phase. External forces, for example perpendicular or parallel electric forces applied to the thin layer chromatographic plates, may effect these processes. In this work, TLC plates were placed perpendicular or parallel to 2.45 ± 0.5 GHz electromagnetic waves (microwaves) to improve chromatographic resolution. Perpendicular arrangement of the microwave field relative to the TLC plate led to the greatest improvement of the separation compared with separation under normal conditions.

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