The concentration of monoclonal antibodies (mAbs) and fusion proteins can be determined by various bioanalytical methods and devices. Among these, affinity high-performance liquid chromatography (HPLC) is considered as the gold standard. As obtaining HPLC results can be very time-consuming, many high-performance alternatives have started to appear on the market. These include the Cedex family of analysers, where product concentration measurements are based on immunoturbidimetry, Octet analysis systems, which are based on bio-layer interferometry, and ValitaTiter IgG quantification assay, which detects changes in light polarization. The purpose of the master’s thesis was to investigate possible discrepancies in measurements between the before-mentioned high-throughput alternatives and HPLC. In addition, we wanted to check whether the separation of the product from larger impurities and whether the freezing of samples affects the measurements of Cedex Bio HT devices. To study the potential influence of recombinant protein molecule structures on device measurements, four CHO cell lines producing IgG1, IgG2, IgG4, and Fc-fusion protein were included in the experiment. During the 14-day production phase, daily sampling of bioprocess slurries took place. We found that the primary separation process and the freezing of the samples prior to analysis does not affect product concentration measurements and that deviations between measurements mainly depend on product concentration, calibration curves, and the structure of the recombinant protein. Among all studied devices or methods, the lowest discrepancies from HPLC were observed on the Octet QK analyser.
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