Assessment of operating conditions affecting the peak capacity of intact protein bioanalysis in hydrophobic interaction liquid-chromatography

With the current increased demand for chromatographic analysis of intact proteins, the need for an in-depth characterization of proteins and protein-derived macromolecules is inevitable. In this regard, hydrophobic interaction chromatography (HIC), which is based on the interaction between hydrophobic patches of proteins and weakly hydrophobic ligands of the stationary phase while maintaining the protein 3D structure, offers a unique possibility for sample characterization. In recent years, the performance of a gradient separation is frequently curbed by assessing the peak capacity, which is defined as the maximum number of peaks that can be separated within the defined gradient window. This study was performed to assess the effects of gradient conditions on the separation of intact proteins. The effect of mobile-phase velocity on peak capacity was assessed at different gradient steepness. Furthermore, the effect of gradient window (and especially gradient starting conditions) on resulting resolution and selectivity were investigated. Finally, optimized gradient conditions were applied to profile intact protein samples, that vary in sample complexity. This study further highlights the efficiency of HIC as a suitable method for biomolecule analysis.