Examples of purification

The removal of copper from the pregnant nickel solution in the Sherritt-Gordon process is an example of purification by precipitation of a fairly insoluble compound. First, in the copper boil step, ammonia is driven off by heating the solution, and some copper sulfide precipitates. The residual copper is removed by a dding hydrogen sulfide for the chemical precipitation of mote copper sulfide. 

As an example of purification via the ELP fusion approach Meyer and Chilkoti (Fig. 9, left), purified the proteins thioredoxin and tendamistat. For this purpose these target proteins and ELP were genetically fused via a short peptide sequence that included a thrombin cleavage site, which allows the removal of the ELP tag after the purification is completed. The general outline of the purification procedure... 

Although most of the sialidases have been purified by classical methods of enzyme isolation, affinity chromatography is now coming more and more into use, as is indicated by the foregoing examples of purification of sialidases. The adsorbent first used for chromatography of sialidases was sialic acid bound to the surface of intact erythrocytes ... 

Because a-L-arabinofuranosidase is an extracellular enzyme, a crude preparation may be made simply by fractionation of the culture filtrate with ammonium sulfate. The enzyme can be purified from the crude enzyme-preparation by some suitable combination of ion-exchange chromatography, gel filtration, and similar techniques. Three examples of purification procedures, two from micro-organisms and one from a plant, are given here. 

The following two examples of purification show how various techniques can be effectively combined to produce purified proteins with minimum effort and loss of activity. 

Figure 15 presents an example of purification of a mouse monoclonal IgG3 antibody from an ascite fluid. 

The main advantage of this method is its ability to eliminate not only impurities such as albumin, but also nucleic acids and possibly endotoxins. This methodology could also be used for the separation of IgM after a few adjustments and method optimization. Figure 25 represents an example of purification of a monoclonal IgGI. 

Figure 18.40 Example of purification by preparative chromatography. Purification of the enantiomers of a benzodiazepinone on 4.6 x 250 mm column of ceUulose tribenzoate coated on 10 Jim silica. Mobile phase, n-hexane-2-propanol (40 60), 0.25 mL/min, at 49oC. (a) Preparative chromatogram, 0.75 mg. (b) Analysis of fractions B (dashed line) and D (soUd line). Reproduced with permission from A. Katti, P. Erlandsson and R. Ddppen, J. Chromatogr., 590 (1992) 127(Figs. 3 and 5).

The adsorption step in a process sequence can be used to remove a contaminant from a fluid stream by contact with a stationary solid adsorbent bed. Is this an example of purification, concentration, or fractionation, and why ... 

Table 6.20 Examples of purification of thorium on an industrial scale by solvent extraction with TBP... 

Therefore, while it is safe to say feat a given UF membrane could separate the much smaller lactose from the much larger protein in whey, it is dangerous to assume that selected proteins could be separated from each other without experimental evidence. All microporous filtration (MF, UF and RO) deals with purification, fractionation, concentration or partition. An example of purification is pressure-driven UF removal of particles and high-molecular-wei t species from water subsequendy to be used in hollow-fiber RO desalination. An example of pressure-driven fractionation is separation of protein and lactose from cheese whey for use as food additives (in the... 

Examples of Purification Processes Prior to EMEW Nickel Electrowinning... 

The first example of purification by selective labelling was described in 1968 for a peptide that was s)mthesized in solution (2). In 1976, Merrifield and co-workers (3) applied this concept to SPPS and demonstrated that peptides bearing an intentionally introduced Cys-Met N-terminal dipeptide can be purified by absorption onto an organometallic immobilized matrix. The native sequence lacking Cys-Met was recovered through a CNBr-mediated Met-X specific cleavage. 

The mineral ore is extracted, crushed, and then purified by chemical means. For examples of purification, see blast furnace (for the smelting of iron ore) Castner-Kellner process (for the production of chlorine) Frasch process (for the production of sulfur). 

Depending on the amount of ligand in hand, the complex can be synthesized and isolated, for instance, by precipitation or by crystallization there are, however, few examples of purification by chromatography (by ionic exchange processes or by mass exclusion). Access to the isolated complex allows full characterization, e.g., by elemental analysis or, to a lesser extent, by high-resolution mass spectroscopy HR-MS (if the complex can be analyzed by such a method). 

Examples of purification processes are presented below, illustrating how the individual techniques are combined to create purification processes. 

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