Liquid-Liquid Equilibrium Data, Viscosities, Densities, Conductivities, and Refractive Indexes of Poly (vinyl pyrrolidone)+ tri-sodium Citrate + Urea Aqueous Two-Phase Systems at Different pH

Mohsen Pirdashti,Kamyar Movagharnejad,Abbas Ali Rostami

doi:10.1590/0104-6632.20170343s20150619

Mohsen Pirdashti, Kamyar Movagharnejad + Show 1 more

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https://doi.org/10.1590/0104-6632.20170343s20150619

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Abstract

Abstract The present study investigated liquid-liquid equilibria of polyvinylpyrrolidone (PVP) K30 + tri-sodium citrate + urea (5% and 10% mass) aqueous two-phase systems at 25°C and pH values of 6.2, 7.4, and 10.0. Results showed that the binodal was displaced toward higher concentrations as the urea concentration increased. The effect of pH, polymer/salt (w/w) ratio, urea concentration, tie line length, and slope of tie line on the partition behavior of urea was examined. The viscosity, density, electrical conductivity, and refractive index of PVP (K30) + tri-sodium citrate + urea + water two-phase systems were measured versus pH value. The relation between tie line length and the density and viscosity of the aqueous two-phase systems was also examined.

Highlights

An aqueous two-phase system (ATPS) is a liquid–liquid extraction strategy that can efficiently separate biological materials such as recombinant protein and enzymes (Albertsson, 1986; Hatti-Kaul, 2000)
Because the electrical conductivity and the refractive index of the phase samples depend on PVP (K30), urea, and salt concentration, calibration plots of the refractive index versus polymer concentration were prepared for different concentrations of salt and urea
To increase the knowledge about ATPSs containing urea, phase diagrams of a range of systems based on PVP (K30) + sodium citrate + water at 298.15 K and pH values of 6.2, 7.4, and 10.0 in the presence of urea (5% and 10% mass) were determined

Summary

Introduction

An aqueous two-phase system (ATPS) is a liquid–liquid extraction strategy that can efficiently separate biological materials such as recombinant protein and enzymes (Albertsson, 1986; Hatti-Kaul, 2000). The present study obtained phase equilibrium data for PVP (K30) + tri-sodium citrate (pH = 6.2, 7.4, and 10.0) + urea (5% and 10% (mass) + water at 25°C.

Results

Conclusion