Phase separation at a sub-zero temperature was first found by our research group. After phase separation, more than 99% of the total hGH or hGHG120R was found in the lower phase and more than half of the organic solvent stayed in the upper phase. This method was also applied to remove organic solvent from other protein and peptide solutions.
Analytical methods, especially HPLC systems, were established to measure the concentration and purity of hGH and hGHG120R solutions. A second-peak phenomenon occurred in the analytical RP-HPLC chromatogram was investigated. The experimental results indicated that this second-peak was probably because of an hGHG120R variant which had a two-chain structure.
A mathematical model based on the rate theory to describe the stationary and mobile phase mass-transfer in an SEC column was presented. The model was used to study the effects of various physical parameters, including the Peclet number (Pe = vL/D b), the Biot number (Bi = kR p/ε p aD p), the η number (η = ε p aD pL/R p 2v), effective diffusivity (D p), packing particle radius (R p), and the ratio of the molecular diameter to the pore diameter (λ, = d m/d pore), on the performance of a low pressure preparative SEC column. The accuracy of the established model was verified by experimental results. The model was also used to predict the performance of the larger preparative SEC column.