Characteristics of mixed reverse micelles from ternary surfactant with di(2-ethylhexyl) tails

To design a novel reverse micellar system for protein extraction, binary an d ternary reverse micellar systems composed of sodium bis(2-ethylhexyl) sul fosuccinate (AOT), di(2-ethylhexyl)phosphoric acid (DEHPA) and di(2-ethylhe xyl) phosphorothioic acid (DEPTA) in isooctane are examined for the water s olubilization and the extraction characteristics of proteins. The AOT-DEHPA -DEPTA ternary surfactant system is found to be suitable for protein extrac tion. The size of the mixed reverse micelle was determined by the small ang le X-ray scattering method. It appears that both the water content and the micelle size for the ternary system are larger than those for the BOT and D EPTA single systems. Hemoglobin was successfully extracted by the ternary s ystem, and back-extraction can be realized by use of a weaker alkaline solu tion (pH9.5) with the addition of a small amount of n-octanol in the organi c phase.