Purification sequences

Yield Losses. The numerous steps incur a built-in yield loss. For example, if only 2% yield loss were to be associated with each step, the overall yield for a purification sequence of 10 steps would be as in equation 1 ... 

Fig. 2. Outline of possible steps in the recovery and purification sequence for recombinant tissue plasminogen activator derived from recombinant CHO...

Independent Assays for Provings Virus Removal. Retrovimses and vimses can also be present in culture fluids of mammalian cell lines (15,24). Certainly the absence of vims can be difficult to prove. Model vimses, eg, NIH Rausher leukemia vims and NZB Xenotropic vims, were spiked into fluids being purified, and their removal subsequently vaUdated when subjected to the same purification sequence as used for the product. 

The goal of these two processes is to provide a closed loop on the plutonium streams in the metal preparation and purification sequence. 

Szwergold, B.S., Howell, S., and Beisswenger, P.J. (2001) Human fructosamine-3-kinase purification, sequencing, substrate specificity, and evidence of activity in vivo. Diabetes 50, 2139-2147. 

SI. Smith, D. M., Tran, H. M., and Epstein, L. B., Two-dimensional gel electrophoresis for purification, sequencing and identification of cytokine-induced proteins in normal and malignant Cells. In Cytokines A Practical Approach (F. R. Balkwill, ed.), pp. 111-128. IRL Press at Oxford... 

Fig. 3. Overview of purification sequence for the nonrecombinant tissue plasminogen activator (t-PA) which also contains urokinase plasminogen activator (u-PA). Serum-free culture conditional media is from normal human cell line. The temperature for all steps, except for size-exclusion chromatography...

Lewis JD, Meehan RR, Henzel WJ, Maurer-Fogy I, Jeppesen P, Klein F, Bird A. Purification, sequence, and cellular localization of a novel chromosomal protein that binds to methylated DNA. Cell 1992 69 905-914. 

From these preliminary data, the objectives and performance criteria of the purification sequence can be defined and, thus, the fundamental basis for designing the most suitable strategy is established. 

As noted earlier, Wollaston collected the undissolved residue from each batch process, and resubmitted the combined residues to a second purification sequence. The purified platinum obtained from the residues was also worked successfully, and we checked the purity of such platinum by combining the residues from both of the procedures we repeated, and purified the crude residue by the second chemical sequence the analytical results are given in Table V. As might be expected, this second treatment with aqua regia much reduces the proportion of platinum in the undissolved residue, and increases the relative amounts of iridium and rhodium. 

The purified platinum is quite similar in types and levels of impurities to that produced by the primary purification sequences. It is therefore apparent why Wollaston found no consistent differences in the metallurgical characteristics of the platinum powder produced from the crude ore or the retreated residuum by either of his two purification processes. 

Pu metal has recently been produced in kilogram batches in a coordinated reduction-purification sequence (pyrochemical processing) with Ca reductant, CaCL flux, and subsequent molten salt Am extraction (9.2.2.6.1), yielding single ingots of Pu metal. ... 

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