Cosolutes effects on aqueous two-phase systems equilibrium formation studied by physical approaches

BERTOLUZZO, MARÍA GUADALUPE; RIGATUSO, RUBÉN; FARRUGGIA BEATRIZ; NERLI BIBIANA; PICÓ GUILLERMO

COLLOIDS AND SURFACES B-BIOINTERFACES

Elsevier Science Ireland Ltd.

Año: 2007 vol. 59 p. 134 - 140

0927-7765

The effect of urea and sodium salts of monovalent halides on the aqueous polyethyleneglycol solution and binodal diagrams of polyethyleneglycol?potassium phosphate (polyethyleneglycol of molecular mass 1500, 4000, 6000 and 8000) were studied using different physical approaches. The effect of these solutes on the binodal diagram for polyethyleneglycol?potassium phosphate was also investigated. The cosolutes affected in a significant manner the water structured around the ethylene chain of polyethyleneglycol inducing a lost of this. The equilibrium curves For the aqueous two-phase systems were fitting very well by a sigmoidal function with two parameters, which are closely related with the cosolute structure making or breaking capacity on the water ordered.