Subcritical water as eluent for chromatographic separation of carbohydrates using cation-exchange resins

Results indicate that increasing temperature affects the separation by decreasing the retention volume and peak width rather than by improving the selectivity. The strong cation-exchanger withstands the subcritical conditions well but some carbohydrates start to degrade at 373 K in water. Depending on the compound, the upper separation temperature limit for the sugars is around 398 K, whereas the sugar alcohols studied are able to tolerate even 423 K. Thus, the elevated temperature is favorable for separation and technically advantageous, especially if the treated feed is already at elevated temperature, e.g. following a hydrolysis process.