title: Improving selectivity in multimodal chromatography using controlled pH gradient elution.
abstract: Externally generated pH gradients are employed on a multimodal cation exchange chromatographic resin to improve the selectivity for a mixture of model proteins. By combining controlled pH gradients with the unique selectivities arising from the multiple interaction types exhibited by the multimodal resin, the separation of the protein mixture is significantly improved as compared to linear salt gradient operation. Several gradient conditions are explored and a shallow gradient from pH 3.8 to 5.5 is shown to be able to resolve the proteins. This work provides proof of concept for the use of pH gradients in multimodal chromatography and sets the stage for future applications.
authors.affiliation: Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
authors.forename: Melissa A
authors.initials: MA
authors.lastname: Holstein
authors.forename: Amir A M
authors.initials: AA
authors.lastname: Nikfetrat
authors.forename: Mark
authors.initials: M
authors.lastname: Gage
authors.forename: Allen G
authors.initials: AG
authors.lastname: Hirsh
authors.forename: Steven M
authors.initials: SM
authors.lastname: Cramer
mesh_terms: D002411:Cation Exchange Resins; D002852:Chromatography, Ion Exchange / Q000379:methods*; D006863:Hydrogen-Ion Concentration
chemical_list: D002411:Cation Exchange Resins