Publications by authors named "Krystian Baran"

3 Publications

  • Page 1 of 1

Influence of the geometry of extra column volumes on band broadening in a chromatographic system. Predictions by computational fluid dynamics.

J Chromatogr A 2021 Sep 14;1653:462410. Epub 2021 Jul 14.

Department of Chemical and Process Engineering, Rzeszów University of Technology, Rzeszów, Poland. Electronic address:

A computational fluid dynamics method was used for prediction of flow behavior and band profiles of small- and macro-molecule compounds eluting in extra-column volumes (ECV) of an Äkta chromatographic system. The model compounds were: acetone, bovine serum albumin and an antibody. The construction of ECV was approximated by different types of geometries, starting from the simplest two-dimensional (2D) arrangement consisting of a straight capillary tube, and ending with a three-dimensional system (3D), which accounted for the flow path curvature of individual elements of ECV, including: injection loop capillary, multi-way valve, connecting capillary and detector cell. The accuracy of the model predictions depended on the flow path length and the eluent flowrate. 2D-geometry models reproduced pretty well the shapes of band profiles recorded at the lowest eluent flowrate used, but they failed for increased flowrates. The 3D-geometry model was found to be sufficiently accurate for all conditions investigated. It was exploited to analyze band broadening in the individual ECV elements. The simulation results revealed that the flow behavior in the injection loop capillaries strongly influenced the shape of band profiles, particularly at higher eluent velocities. This was attributed to the formation of Dean vertices triggered by centrifugal forces in curved parts of the eluent flow path.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.chroma.2021.462410DOI Listing
September 2021

A high-throughput method for fast detecting unfolding of monoclonal antibodies on cation exchange resins.

J Chromatogr A 2020 Dec 11;1634:461688. Epub 2020 Nov 11.

Department of Chemical and Process Engineering, Rzeszów University of Technology, Rzeszów, Poland. Electronic address:

A fast method for assessing the stability of monoclonal antibodies (mAbs) adsorbed on ion exchange resins has been developed. The method exploited a real time polymerase chain reaction equipment to determine the temperature of protein phase transition, i.e., the so called melting temperature, based on differential scanning fluorimetry. Changes to the melting temperature were screened under various adsorption conditions and correlated with the protein stability upon adsorption. The method was tested for two different mAbs bound to various types of strong cation exchangers at different pH and loading concentrations. The mAbs destabilized upon adsorption due to strong binding, which manifested itself in aggregate formation and recovery reduction. The phenomenon depended on the resin type and binding conditions. However, regardless of the process conditions and resins used, drop in the melting temperatures to a critical value of about 30° could serve as an indicator of destructive changes in the protein structure in the adsorbed phase. The measurements were simultaneously accomplished for a number of samples with very small material consumption. Therefore, the method may be applied for screening resins and operating variables for a given mAb to exclude conditions that induce structure destabilization and aggregation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.chroma.2020.461688DOI Listing
December 2020

Effect of flow behavior in extra-column volumes on the retention pattern of proteins in a small column.

J Chromatogr A 2019 Aug 2;1598:154-162. Epub 2019 Apr 2.

Department of Chemical and Process Engineering, Powstańców Warszawy Ave. 6, 35-959, Rzeszów, Poland. Electronic address:

Experimental and theoretical analysis of deformation of band profiles in extra-column volumes (ECV) was performed, and its influence on the retention pattern of proteins in a small chromatographic column was quantified. Several macromolecule and small-molecule compounds, and their mixtures were eluted from a chromatographic system in the absence and presence of the column. The peak deformation in ECV was attributed to non-uniform velocity distribution in the radial direction in connecting capillaries. The phenomenon enhanced with increasing molecular weight of the model compound, when radial diffusion dominated the mechanism of band spreading. The band shape was also affected by the geometry of the injection system used, i.e., an injection loop capillary or a superloop. The phenomenon vanished for a small molecule compound, for which plug flow conditions could be established. The difference in flow behaviour of the macromolecule and small-molecule compounds caused them to migrate with different velocities in ECV, which resulted in partial separation of their bands. The ECV effect influenced the retention behaviour of macromolecules in a small column; it caused tailing of peaks and asymmetry of breakthrough curves. To describe the elution profiles in ECV and in the column, a mathematical model was used which accounted for non-ideality of the flow pattern. The model reproduced accurately band profiles of macromolecules within a range of relatively low velocities, typical however for protein chromatography.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.chroma.2019.03.060DOI Listing
August 2019
-->