Effect of ethanol content on mass-transfer parameters and hetp indexes of amino ACIDS in a poly-4-vinylpyridine chromatography

A series of fundamental tasks required for the development of a solvent gradient simulated moving bed (SG-SMB) chromatography for amino acid separation were performed in this study. First, the mass-transfer parameters of amino acids in the chromatographic column packed with poly-4-vinylpyridine resin (i.e., the adsorbent of the SG-SMB) were estimated while varying the content of ethanol in the mobile phase. Then, the effect of ethanol content on the mass-transfer parameters of amino acids was analyzed. To describe the effect in a quantitative or a mathematical manner, proper mass-transfer equations were developed and the related parameter values were determined. The developed mass-transfer equations and the determined parameter values were validated with experimental chromatogram data, and they will be highly useful in the stage of designing the SG-SMB because they can be incorporated into the model equations of the SG-SMB. Furthermore, the HETP (Height Equivalent to a Theoretical Plate) indexes of amino acids were evaluated while varying ethanol content and liquid velocity. The results showed that an increase in the ethanol content led to an increase in the HETP on the whole. In addition, the intra-particle diffusion was found to become a controlling factor in the HETP as the liquid velocity increased. The results of this study will be of great value in the stage of developing the SG-SMB chromatography for amino acid separation. ©