Liquid-liquid equilibria, electrical conductivity, and refractive indices of Poly(ethylene glycol) + sodium sulfate + guanidine hydrochloride aqueous two-phase systems: Correlation and thermodynamic modeling

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• 作者：Mohsen Pirdashti^a ; ^{pirdashti@yahoo.com" class="auth_mail" title="E-mail the corresponding author} ; Kamyar Movagharnejad^a ; ^{Movagharnejad@yahoo.com" class="auth_mail" title="E-mail the corresponding author} ; Abbas Ali Rostami^b ; ^{rostami@umz.ac.ir" class="auth_mail" title="E-mail the corresponding author} ; Hamid Bakhshi^a ; ^{h.bakhshi@nit.ac.ir" class="auth_mail" title="E-mail the corresponding author} ; Poorya Mobalegholeslam^c ; ^{pm.biochemical@yahoo.com" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Aqueous two-phase system ; Phase diagram ; Denaturants ; Activity coefficient ; Extended Pitzer model ; Extended UNIQUAC model
• 刊名：Fluid Phase Equilibria
• 出版年：2016
• 出版时间：15 June 2016
• 年：2016
• 卷：417
• 期：Complete
• 页码：29-40
• 全文大小：1570 K

文摘

The initial recovery steps for recombinant protein were carried out using aqueous two-phase systems in the presence of guanidine hydrochloride. To investigate the phase behavior of such systems, equilibrium data was obtained for molecular weight fractions of PEG (3000 and 6000) + sodium sulfate (pH 7) + guanidine hydrochloride (5% and 10% mass) + water at 25 °C. Displacement of the binodal toward higher concentrations through an increase in guanidine hydrochloride concentration was clearly observed. A slightly larger two-phase was obtained as the PEG molecular weight increased from PEG 3000 to 6000. The experimental binodal data of the system was successfully correlated with Bleasdale equations (high R² and low SE). The effects of molecular weight, guanidine hydrochloride concentration, tie-line length, and slope of tie-line on the partition behaviors of guanidine hydrochloride were examined at constant pH. The compositions of each aqueous phase were calculated using two thermodynamic models for the activity coefficient. The calculated results showed that the extended Pitzer and extended UNIQUAC models can predict the data in the quaternary system well. The fitted binary interaction parameters of the models were reported.