ABSTRACT
This chapter examines the consequences of secondary chemical equilibria on both the thermodynamic and kinetic behavior of peptides and proteins in high-performance liquid chromatography (HPLC) systems. It provides additional theoretical framework for the assessment of regular and non-regular elution behavior of peptides and proteins particularly evident with the adsorption modes of HPLC. The chapter discusses the examples of the participation of chemical equilibria, namely ion pair interactions and introduces conformational interconversions and their effect on retention and zone broadening behaviour. The value of the quantitative relationships and associated analytical approaches can be found in the following extensions of chromatographic theory and experimentation as it applies to peptide and protein separations: determination of conformational behavior during the separation and definition of interactive contact areas. Chromatographic elution can then be interpreted in terms of isocratic or gradient elution relationships depending on the nature of the mobile phase composition.
