Determination of aldoses and ketoses by GC-MS using differential derivatisation.

摘要

A method was developed to determine aldoses and ketoses in plant materials simultaneously. Monosaccharides were extracted by sonication with 80% ethanol and sugar oximes formed by treatment of the resultant extract with hydroxylamine and pyridine at 90 degrees C. After reaction, one aliquot of the product was derived with acetic anhydride at 90 degrees C, while a second aliquot was silylated with HMDS and TMCS at 80 degrees C. Both reaction mixtures were analysed by GC-MS in the SIM mode. Quantivation was linear within the range 1-4 micro g/ml and the detection limit for monosaccharides was 5-25 ng/ml. The absolute recoveries were between 73.0 and 90.2% and the RSDs were 3.1-10.0%. This method was applied to analyse the free monosaccharides in Lyceum barbarum [Lycium barbarum]. Eight monosaccharides were present with amounts between 0.26 and 368.65 micro g/mg..