Capillary Chromatography Based on Tube Radial Distribution of Ternary Mixed Solvents: Construction of the Phase Diagram and the Separation Performance

摘要

Open-tubular capillary chromatography using a ternary solvent mixture consisting of water-hydrophilic-hydrophobic organic solvent as a carrier solution has been developed. When the ternary carrier solution is fed into the capillary tube, the carrier solvents are radially distributed and generate inner and outer phases in the tube. The outer phase functions as a pseudo-stationary phase in chromatography. In this study, investigations proceeded with reference to the solubility curves on the phase diagram of the ternary mixed solvents at 5 and 20℃. Model analytes, 1-naphthol and 2,6-naphthalenedisulfonic acid (2,6-NDS), were examined with ternary water-acetonitrile-ethyl acetate solvent mixtures as carrier solutions and a fused-silica capillary tube (50-μm inner diameter). They were separated in this order with organic solvent-rich carrier solutions, while, in the reverse order with the water-rich carrier solutions at a tube temperature of 5℃.