Solubilization of hydrophilic compounds in 1,1,1,2-tetrafluoroethane with a cationic surfactant

Solubilization of hydrophilic compounds was examined in liquid 1,1,1,2-tetrafluoroethane (R134a) in the presence of the cationic surfactant trioctylmethylammonium chloride (TOMAC). The absorption spectra of methyl orange in the TOMAC-containing R134a solutions were obtained. Significant blue shifts were observed in comparison with the spectrum of methyl orange in aqueous solution. The shifts decreased as the water-to-surfactant ratio, W0, increased. In addition, spectral measurements confirmed the dissolution of cytochrome c in R134a in the presence of TOMAC. R134a remains as a liquid under mild applied pressure and becomes gas under ambient conditions; it therefore separates from analytes of interest directly without further concentration when used as an extraction solvent. Accordingly, it may be applied to recover valuable hydrophilic substances of low concentration from aqueous solutions.