Our first idea that could explain the discrepancies between the two ion maps was that maybe one method is more sensiWve towards certain hexose. This would be good news because it would mean having a selecWve technique for analyzing different hexoses. Nevertheless, judging from the MS/MS spectra of different hexoses and comparing them with MS/MS spectra from the Wssue, it is impossible to disWnguish between them, except fructose.