A New Separation Method Using Aqueous Mixed Solvents and an Open Tubular Capillary without Any Separation Column

In this research, the new separation method based on micro solvent cluster extraction and preferential solvation has been described. A proposed separation method using aqueous mixed solvents of organic solvents (acetonitrile, 1-propanol, 2-propanol and 1,1,1,3,3,3-hexafluoro-2-propanol) or ionic liquids and an open tubular capillary has been separated the model compounds (2-naphthol, 4-nitroaniline, phenol, 4-chlorophenol, 4-nitrophenol and 1,3,5-naphthalenetrisulfonic acid) sufficiently during their flow in a fused silica capillary tube (50 μm in I.D. and ca. 45 cm in length) without a specific separation column. For organic solvents, the separation power of the proposed method is due to salt enhanced micro-phase separation of the mobile phase between the capillary wall and the center of capillary tube. The model compounds have been also separated by using ionic liquids in water due to the formation of micro-solvent cluster formation of ionic liquid in the mixed solvent that was suggested by LAXS data. Moreover, the polymer added in the BMIMCl/H2O mixed solvents enhances the aggregation of ionic liquid around the polymer in the mixed aqueous solution.The increased micro-solvent clusters of the ionic liquid increase theoretical plate number and separation factor. Aromatic compounds are concentrated in the ionic liquid clusters around and polar or ionic compounds are concentrated in the water phase