W Kopaciewicz

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Several high-performance stationary phases suitable for protein chromatography were synthesized. Columns packed with these materials could be operated independently in either the anion-exchange or hydrophobic-interaction mode. Two approaches were used to prepare these materials. In the first method, a polyamine was adsorbed on the surface of macroporous(More)
Several anion-exchange stationary phases (based on polyethyleneimine-coated silica) were synthesized so as to vary in ligand density and hydrophobicity. These materials were first examined for hemoglobin-binding capacity and then evaluated chromatographically. Protein binding, retention and resolution increased concomitantly with ligand density. Ferritin(More)
Proper mobile phase selection significantly improved high-performance ion-exchange fractionations of proteins. The pH and salt content of the eluant affected chromatographic behavior on both strong and weak ion-exchange columns. The retention and resolution of a number of proteins was examined on strong and weak ion-exchange supports with regard to these(More)
The effect of mobile phase pH on the retention characteristics of eleven proteins was examined in hydrophobic interaction chromatography (HIC) on a SynChropak propyl stationary phase. Selectivity was shown to change with eluent pH. The effect of the displacing salt on the separation of proteins on a weakly hydrophobic weak-anion-exchange chromatography(More)
We have described the preparation and chromatographic evaluation of an adsorbed hydrophobic stationary phase suitable for reversed-phase chromatography of proteins and peptides. The synthetic procedure involves three steps: the adsorption of a polyamine to the silica surface; crosslinking of the adsorbed polyamine layer with a bis-phenyl difunctional(More)
Properties of the matrix and stationary phase which affect the intrinsic loading capacity of silica-based packing materials for preparative anion-exchange chromatography of proteins were investigated. Polyethyleneimine-coated controlled porosity glass beads ranging from 100 to 2000 A in pore diameter were used to evaluate the effects of pore diameter and(More)
Several silica-based anion-exchange packings were synthesized with nominal pore sizes of 250, 500 and 1000 A in 10-, 20- and 50-micron particles. The static ("equilibrium") adsorption capacities for bovene serum albumin (mol. wt. 69,000), alpha-lactalbumin (17,500) and ferritin (440,000) were first measured using bulk material. The media were then packed(More)
We have prepared several silica-based cation-exchange materials that were suitable for the high-performance liquid chromatography of basic proteins. Two synthetic routes were examined. Central to both procedures was the adsorption of a low molecular weight polyamine. One method crosslinks the adsorbed polyamine with a multifunctional oxirane, which is then(More)
Purification of proteins is commonly a multiple-step process involving size exclusion, ion exchange, affinity, hydrophobic, and other modes of chromatography. In an effort to circumvent the laborious process of collecting the solutes from each column and reintroducing them onto a second column, a valving system is described that directs the samples eluted(More)
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