Electrophoresis, column

The tendency for ferritin to aggregate is shown 135, 136) by its heterogeneity as demonstrated on gel electrophoresis, column chromatography, ultra-centrifugation, and many other techniques. This association is readily reversible. The re-examination of any single ferritin fraction isolated from a mixture will show at least four fractions similar to the original preparation. This association is a function of the protein subunit surface of the molecule. Apoferritin molecules behave in a quite similar fashion 137) the iron core has little if any effect. 

As a result, intact molecular ions are formed in high yield. The instrument can be interfaced readily to HPLC or capillary electrophoresis columns and sub-femtomole amounts of proteins can be detected. A disadvantage is that salt concentrations must be kept low (< mM) and that the protein tends to bind Na+, K+, and anions that may confuse interpretation of spectra. 

To reduce adsorption of cellulose powder (T2) Flodin introduced ethanol-treated cellulose as a supporting medium for zone electrophoresis columns (FI). The main advantage is low adsorption, so that the column can be eluted and used over and over again. In the large models up to 2 liters of serum are separated, while microcolumns are under development which should give excellent results for clinical work (PI, Tl). 

Some argue that miniaturized tools for both chemical synthesis and analysis need to be integrated onto a single chip to gain the true benefits of miniaturization [57], not least because of the problems associated with subsystem interconnectivity, dead volumes and chip-to-world interfaces. Demonstrations toward such a goal include, for example, a hyphenated mixing reaction channel coupled to a capillary electrophoresis column [58]. 

Ionic components a and ft, after being driven through a capillary electrophoresis column by an electrical field for 10 min, form bands (zones) whose centers are located at 8.714 and 9.035 cm from the inlet, respectively. Their widths are 0.350 and 0.442 cm, respectively. Calculate the resolution of the two bands. 

Various technologies have been used to measure plasma lipids and lipoproteins and lipoprotein subfractions, including enzymatic, immunochemical, and chemical precipitation reagents, and physical methods, such as ultracentrifugation, electrophoresis, column chromatography, and others. Such methods have been reviewed extensively. As mentioned earlier, however, the cholesterol content of any particular lipoprotein class can vaiy somewhat from individual to individual. Moreover, although different methods of lipoprotein separation may produce similar lipoprotein fractions, they usually do not produce identical fractions, giving rise to systematic biases between methods that purport to measure the same component. The present discussion focuses primarily on methods and procedures commonly used in clinical practice for lipid and lipoprotein measurements. 

It has been shown that the plate count Af of a capillary electrophoresis column is given by... 

Datta, R. Yoshisato, R. A. Carmichael, G. R. "Etevelopment of a Theoretical Model for Continuous Rotating Annular-Bed Electrophoresis column for biochemical separations" AIChE Symposium Series 250, Vol. 82,1986, pp 179-192. 

YOSHISATOETAL. Continuous Rotating Annular Electrophoresis Column 287... 

YOSHISATOETAL. Continuous Rotatu Annular Electrophoresis Column 293... 

Figure 3. Packed-Bed Electrophoresis Column (PBEC) Apparatus...

YOSHISATO ET AL. Continuous Rotating Anmdar Electrophoresis Column 299... 

Figure 4. The Boltz-Todd separation column. (A) Diagram of the electrophoresis column. For a description see Section IV.2.B. (B) Cooling finger and loading device stippling represents cellular suspension. [Redrawn from Boltz and Todd (1979) with kind permission of Dr. P. Todd and Elsevier Biomedical Press.]...

As prototypic mammalian cells, erythrocytes have been used almost solely to test the resolving power of density gradient electrophoresis columns. To perform a large number of tests, erythrocytes may be fixed by dilute aldehyde solutions (Vassar et al., 1972) to obtain particles that are chemi-... 

Pigments with very similar structures might be difficult to separate using classic RP-C18 HPLC. This is the case of zeaxanthin and lutein. To overcome this difficulty, a particular HPLC method should be applied (Darko et al., 2000). Alternatively a capillary electrophoresis column can be used. This last method was successfully applied to the separation of zeaxanthin and lutein from eye humor (Karlsen et al., 2003). The good separation and the fast elution of the pigments obtained by these authors suggest that capillary electrophoresis is suitable for routine analysis of pigments contained in tiny samples. 

A number of apparatuses were constructed for this purpose [257-264], some of which are commercially available. Here we describe the apparatus marketed by LKB (Bromma, Sweden) (see also Ref. 264) (Fig. 6.26). The apparatus consists of a inverted U-shaped tube that is composed of two parts connected by a joint in the upper part. One limb accommodates the electrophoresis column that is surrounded by a covering jacket, the other limb filled with buffer serves to make connection with the electrode vessel. At the lower end of the column a collecting funnel is attached. Liquid connection or disconnection between the two limbs can be done through a ground female joint. The stopcock above this joint connects the system to a buffer reservoir when the column is washed or when the zones are eluted. In the male joint of the top piece there is a hole that allows liquid to pass to the other limb. By turning the liquid stream can be disconnected at this point. The column size is 55 X 2 cm Sephadex or cellulose serve as the supporting material. Separation is run at 500-1000 V and 25-50 mA. 

The advantage of isotachophoresis from the point of view of preparative scale operations is the increase in resolution with increasing load. A higher load increases the length of individual zones. Separation is carried out in an adapted LKB prepara-tive electrophoresis column (Uniphor) and the following buffer systems are recommended by Svendsen [293]. 

Figure 9.23 Electropherogram showing separation of alkali and alkaline earth metals and ammonium by capillary electrophoresis column and conditions as detailed in text. Peaks (1) NHj, (2) K+, (3) Ca +, (4) Na+, (5) Mg +, (6) Sr +, (7) Ba2+ and (8) Li+. (Reproduced by permission of Dionex UK Ltd.)...

A multichannel instrument is a powerful tool for studies of transient intermediates in moderately fast reactions, for kinetic studies, and for the qualiiaiive and quantitative determination of the components exiting from a liquid chromatographic column or a capillary electrophoresis column. They arc also useful for general-purpose satnningexperiments, Some have the software necessary to analyze the lime dependence at four or more wavelengths for kinetic studies. 

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