Optimization of experimental conditions for the separation of small and large starch granules by gravitational field-flow fractionation

Separation of small and large barley starch granules by gravitational field -flow fractionation was investigated from the point of view of sample pre-t reatment, amount of injected sample, and elution conditions. The sample pre -treatment study resulted in the conclusion that it is reasonable to soak t he starch granules for at least 24 h prior to separation. The experiments w ith different amounts of injected sample show that it is possible to increa se as well as decrease twofold the sample amount usually used without any c hange in retention ratios. The implementation of flow-rate gradients for el ution of the starch granules reduced total separation time. However, the ap plied flow-rate gradients did not improve the resolution of peaks A and B c ompared with the generally used constant flow-rate. Thus, for barley starch granules, the constant flow-rates within the range from 0.8 to 1.0 ml/min seem to provide the best compromise of total separation time, peak resoluti on and instrumental expense. (C) 2001 Elsevier Science B.V. All rights rese rved.