Phase separation and molecular weight fractionation behaviour of maltodextrin/agarose mixtures

Fourier transform infrared (FTIR) spectroscopy, in combination with multivariate data analysis (multivariate curve resolution, MCR) is used to determine the phase compositions of bulk separated agarose/maltodextrin mixtures. Much higher concentrations of maltodextrin are found in the agarose rich phases than would be expected from the cloud point curve determined for this system. It is also shown that tie-line behaviour depends on the initial maltodextrin concentration. High performance size exclusion chromatography measurements on the separated phases suggest that this is due to a strong molar mass fractionation of maltodextrin during the phase separation.