Effect of method of solution on observed molecular weight distribution of barley starch and starch derivatives in size exclusion chromatography

Summary Samples of native barley starch and six starch derivatives were suspended (0.1% sample concentration) in four different solvents: the eluent (pH 11 buffer), dimethylsulfoxide, 0.1 M NaOH or 0.5 M NaOH and kept in a boilling water bath for 5 to 60 minutes or shaken for 60 minutes. The average molecular weight values, and the polydispersity value were determined with a TSK PW-type column using narrow standard calibration. Only a small part of the samples dissolved in the eluent. The dissolution of sample in dimethylsulfoxide was dependent on sample type. Of the NaOH solutions, 0.5 M NaOH was the only one that dissolved all the samples. Therefore, 0.5 M NaOH appears to be the solvent of choice for starch molecules.