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Solvent extraction is an effective method for purufucation of wet process phosphoroc acid. The aim of this study was purification of wet-process phosphoric acid using acid grade phosphorus pentoxide and minimization of fluoride and arsenic. The first step included the pre-purification which was done by discoloration of acid and clarification during which the impurities were reduced. Fluoride reduction rate of about 68% was significant at this step. In the following step, liquid-liquid extraction was used to purify the phosphoric acid from previous stage. The parameters of phase ratio, two-phase contact time and the fluid flow regime in a packed column of the fluidized bed were studied using 2-ethylhexanol as a basic solvent. The results of this part have been used as an evaluation of acid extraction yield and separation factor of impurities using an experiment designed by the Taguchi method. Arsenic, fluoride and phosphorus pentoxide concentration were measured using Inductivity Coupled Plasma (ICP) and Ion Chromatography (IC) analysis. The optimal level of parameters and their effect was obtained. By comparing the optimal and worst level in extraction step, it was found that the amount of acid extracted can vary from 23% to 73%. Furthermore, the removal rate of 49% for fluoride and 67% for arsenic in the worst conditions, can increase to the optimal conditions as much as 72% and 93%, respectively. The overal removal rate of 92% for fluoride and 96% for arsenic in two stages were achieved. Increasing of phase ratio, the time as well as increasing the flow regime created optimal conditions in the extraction section. [ABSTRACT FROM AUTHOR]

A simple single step ion exchange chromatography method has been developed for purification of SA from plant cell culture extracts. The optimum washing and elution solvents are 25 mM sodium phosphate (pH 7.0-7.5) and 0.3 M HCl in 60% acetonitrile, respectively. Using the developed method the SA recoveries were found 69-80% calculated from the whole purification process. In particular, in the second 10 mL elution, 70 µg SA in 1 g resin yielded 65% SA recovery, which provided a well-detectable amount of SA with a relatively low level of impurities as analyzed by 400 MHz 1H-NMR. [ABSTRACT FROM AUTHOR]

Purification of green fluorescent protein from a crude solution has been investigated using a combined system of ion-exchange chromatography and size-exclusion chromatography packed into one column of a continuous annular chromatograph. Performing the chromatography with two different sorbents packed into a single column reduces transfer losses and the hold steps between the two separation steps can be eliminated. Appropriate running conditions for the continuous separation mode were achieved by searching for optimal ones in conventional batch-wise operation. Green fluorescent protein was expressed in Saccharomyces cerevisiae, enzymatically lysed and the extract was used as the feed stock. Superdex 200 prep grade was packed into an annular chromatograph (outer diameter: 15 cm, inner diameter: 14 cm) and on top a 1.5 cm layer of the anion-exchange sorbent Source 30 Q. Green fluorescent protein was enriched by the anion-exchange resin and further purified by the size-exclusion gel. Purity was analyzed by sodium dodecyl sulfonate–polyacrylamide gel electrophoresis (SDS–PAGE), Western blotting, fluorescence intensity, and analytical size-exclusion chromatography. [ABSTRACT FROM AUTHOR]

The reproducibility of ion exchange columns was investigated by rigorously evaluating critical chromatographic parameters as well as the performance of these ion exchange columns under various modes of operation. A detailed set of experiments were carried out to determine equilibrium Steric Mass Action parameters, HETP, column dead volume, total ion capacity, and porosity. In addition, the performance of these columns was examined under isocratic, analytical linear gradient, overloaded linear gradient, frontal, and displacement chromatographic conditions. While differences between the two lots were observed with isocratic experiments, the columns exhibited similar behavior under gradient, frontal, and displacement conditions. Furthermore, simulations obtained with the SMA model were shown to predict column performance under linear and non-linear conditions. [ABSTRACT FROM AUTHOR]