HPLC analysis of glucose and fructose in raw sugars

Glucose, fructose and RS concentrations in raw sugars were measured by high pH anion exchange chromatography HPLC coupled with pulsed amperometric detection (PAD). Baseline separation was achieved between glucose, fructose and sucrose and detection sensitivity was adequate to measure RS levels down to 0.01%. The method is less labour intensive than the current Lane and Eynon titration method and also gives more specific results which are less likely to suffer from interference from impurities. Results obtained from the analysis of 223 samples from the 1996 season showed an overall correlation between the two methods of R2=0.95. Results of glucose + fructose by HPLC were on average 6.1% lower than RS levels obtained by the Lane and Eynon method.