Matthias Joehnck

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A novel cation-exchange resin, Eshmuno™ S, was compared to Fractogel® SO3(-) (M) and Toyopearl GigaCap S-650M. The stationary phases have different base matrices, and carry specific types of polymeric surface modifications. Three monoclonal antibodies (mAbs) were used as model proteins to characterize these chromatographic resins. Results from gradient(More)
This review focuses on capillary electrophoretic separations performed on capillary electrophoresis chips (CE chips) with hydrodynamically closed separation systems in a context with transport processes (electroosmotic flow (EOF)) and hydrodynamic flow (HDF)) that may accompany the separations in these devices. It also reflects some relevant works dealing(More)
A two-step chromatography process for monoclonal antibody (mAb) purification from clarified cell culture supernatant (cCCS) was developed using cation exchange Multicolumn Countercurrent Solvent Gradient Purification (MCSGP) as a capture step. After an initial characterization of the cell culture supernatant the capture step was designed from a batch(More)
The cation-exchange capture step of a monoclonal antibody (mAb) purification process using single column batch and multicolumn continuous chromatography (MCSGP) was modeled with a lumped kinetic model. Model parameters were experimentally determined under analytical and preparative conditions: porosities, retention factors and mass transfer parameters of(More)
A fast isocratic HPLC method for analysis of steviol glycosides from Stevia rebaudiana leaves was developed with a high selectivity for nine known steviol glycosides and low eluent consumption. The analytical method was performed on a Purospher® STAR RP-18 endcapped 3 μm Hibar® RT 250-4.6 column at 50 °C with an eluent composition of water (65 vol. %) and(More)
The performance of functionalized materials, such as cation exchange resins, is dependent not only on the ligand type and ligand density, but also on the pore accessibility of the target molecule. In the case of large molecules such as antibodies this latter parameter becomes crucial, because the size of such molecules falls somewhere inside the pore size(More)
In protein chromatography, the size of the protein determines which fraction of pores it can access within a resin and at which rate of diffusion. Moreover, in the presence of grafted polymers like in advanced materials, adsorbed proteins and electrolytes complicate the interaction pore-protein. In this study, we evaluated in a comparative way the behavior(More)
A set of chromatographic materials for bioseparation were characterised by various methods. Both commercial materials and new supports presenting various levels of rigidity were analysed. The methods included size-exclusion and capillary phenomena based techniques. Both batch exclusion and inverse size-exclusion chromatography were used. Gas adsorption,(More)
The use of a poly(methylmethacrylate) chip, provided with two separation channels in the column-coupling (CC) arrangement and on-column conductivity detection sensors, to electrophoretic separations of a group of inorganic anions (chloride, nitrate, sulfate, nitrite, fluoride and phosphate) that need to be monitored in various environmental matrices was(More)
This feasibility study deals with column switching in zone electrophoresis (ZE) separations on a column coupling (CC) chip. The column switching implemented into the ZE separations an on-chip sample clean up applicable for both the multicomponent and high salinity samples. In addition, complemented by different separation mechanisms in the coupled columns(More)