Surfactantes como agentes moduladores da partição e formadores de novos sistemas aquosos bifasicos

Abstract

In the study of aqueous biphasic systems, the micellar two-phase aqueous systems formed by non-ionic surfactants, such as those of the Triton X class, are ideal for extracting biomolecules with strong hydrophobic characteristics, due to their ability to generate hydrophobic environments in the interior of the system phases. Thus, new ATPSMs were characterized from combinations of aqueous solutions of Triton X-114 with aqueous solutions of polyethylene glycol (PEG) type polymers under different composition and temperature conditions. Phase separation leads to the formation of the polymer-enriched upper phase with about 18.0% PEG, 0.50% Triton X-114 and 81.5% water, while the values observed for the lower phase vary in around 15.73% of PEG, 7.84% of Triton X-114 and 76.43% of water in mass percentage. It was observed that the new systems do not have a strong temperature dependence within the temperature range of 278.15 to 293.15 K. In addition, the equilibrium data and the binodal curves were fitted with the linear expressions Othmer-Tobias, Bancroft, Hand and Setschenow and applied to the Flory-Huggins model. All models showed a significant correlation between the data at the 5% significance level with correlation coefficients higher than 0.80. Dyes from the crude extract of urucum (Bixa orellana L.) seeds were partitioned into SABs formed by polyethylene glycol (1500 or 4000 or 6000 g mol-1) or triblock copolymer L35 (2000 g mol-1) + sodium citrate + water in the presence of CTAB (cetyltrimethylammonium bromide). The hypothesis investigated was that the use of surfactants as additives in traditional biphasic aqueous systems can improve the solubility of urucum extract in the phases of these systems through a mechanism of formation of mixed micelles, which proved feasible, since the dyes bixin and norbixin were preferentially concentrated in the lower phase, showing a strong dependence on the temperature and composition of the system. In the presence of surfactant, the dyes were concentrated more in the inferior phase of the studied systems, demonstrating the potential of the micellar biphasic aqueous systems as a new method of extracting and / or purifying the dyes from the urucum seed extract.