Starch analysis using hydrodynamic chromatography with a mixed-bed particle column

Columns packed with commercial glass beads 5 and 19 μm average size and a mixture of both (0.7 volume fraction of large particles) were used to analyse starch composition by hydrodynamic chromatography (HDC), applying water as mobile phase. To obviate retrogradation, experiments were carried out at column temperatures of 15 and 3 °C and several types of starch were assayed. In what concerns amylopectin and amylose separation, a better resolution and a lower pressure drop were obtained for the mixed binary packing when compared with the packing containing uniform 5 μm glass beads. A more efficient cooling of the mobile phase was also obtained with the mixed packing, which was determinant for improving resolution. For the Hylon VII starch the relative retention times (RRT) were 0.777 and 0.964 for amylopectin and amylose, respectively, while for the Tapioca starch the obtained RRTs were 0.799 and 0.923. Application of unbound glass beads as column packing not only might reduce equipment and running costs in preparative scale separations, but also proved to be useful as a fast and reliable method to monitor the amylose and amylopectin content of starch samples of different sources.