Chemical separation speed

In most chemical separation procedures, the goal is to selectively transfer the species of interest from one phase to another, leaving behind any unwanted species. The phase-to-phase transfer is rapid, but the procedures to place the species in the proper form for transfer to occlu are slow. The goal of rapid radiochemical separations is to speed up existing chemical procedrues or to use new, very fast chemical transformations. 

Buffer compatibility Mechanical rigidity Limiting pressure drop Separation speed Deformation properties Particle size distribution Pore size distribution Thermal stability Chemical stability pH limitation Specific surface area Resolution Capacity Mass recovery Biological recovery Regeneration in base Cost ( per g)... 

Atomic absorption spectrometry has been applied to the analysis of over sixty elements. The technique combines speed, simplicity and versatility and has been applied to a very wide range of non-ferrous metal analyses. This review presents a cross section of applications. For the majority of applications flame atomisation is employed but where sensitivity is inadequate using direct aspiration of the sample solution a number of methods using a preconcentration stage have been described. Non-flame atomisation methods have been extensively applied to the analysis of ultra-trace levels of impurities in non-ferrous metals. The application of electrothermal atomisation, particularly to nickel-based alloys has enabled the determination of sub-part per million levels of impurities to be carried out in a fraction of the time required for the chemical separation and flame atomisation techniques. 

In order to improve the separation efficiency and speed in biopolymer analysis a variety of new packing materials have been developed. These developments aim at reducing the effect of slow diffusion between mobile and stationary phase, which is important in the analysis of macromolecules due to their slow diffusion properties. Perfusion phases [13] are produced from highly cross-linked styrene-divinylbenzene copolymers with two types of pores through-pores with a diameter of 600-800 mu and diffusion pores of 80-150 nm. Both the internal and the external surface is covered with the chemically bonded stationary phase. The improved efficiency and separation speed result from the fact that the biopolymers do not have to enter the particles by diffusion only, but are transported into the through-pores by mobile-phase flow. 

Chromatography is the most versatile chemical separation method we have available at present. In it, a mixture is separated into various components on the basis of differences in the speed at which these components move through a chromatographic column. What differentiates their speeds is that the column slows them down by one mechanism or another. Many different retarding effects can be exploited, based on such diverse molecular properties as solubility, charge, size, adsorption, or biochemical affinity. Here we will consider partition chromatography, which is based on differences in (solvation) energy. 

Abstract The history, theoretical fundamentals, and practical application of thermochromatography are briefly reviewed. The main advantages of the method - the speed and selectivity of chemical separation of complex mixtures of short-lived radionuclides, including transactinide ones - are analyzed. Prospects of thermochromatography in production of radionuclides widely used in science and technology are considered on the basis of the performed systematic investigations of the thermochromatographic behavior of volatile compounds of the elements of the periodic table. 

Chemical Separation Procedure. PREPARATION. The Irradiated ore and soil specimens are dissolved by digestion In a mixture of concentrated nitric, hydrofluoric, perchloric, and sulfuric acids. (Additional hydrofluoric acid cem be added If a residue of silica remains In the bottom of the crucible.) After dissolution, the san le Is concentrated to heavy sulftirlc acid fximes, cooled, and transferred to a 15-ml. centrifuge tube. If a residue (sulfate salts) remains after the transferthe solution Is centrifuged for 5 minutes, the supernatant transferred to another tube, and the residue washed with 1 ml. of IM nitric acid. The wash Is added to the supernatant and the residue discarded. (Centrifugation Is always for.the stipulated time and at full speed.) The sample Is then further processed by the procedure reported herein. 

Then add a bit of NaHCOs (4 grams) and salt to saturate solution. Stir a bit more. Separate layers, Extract one more time and distill. Time depends on reaction speed. Reaction speed depends on the amount of catalyst and temperature. 60 C seems to be good, more catalyst, less time. More temperature May be more byproducts, this is what happen when acetic acid is the solvent. Probably a good way will be also acetic acid and 40-50 C, but dual phase is easy to extract ans uses less chemicals. 

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