Origin of the [M − H]+ ion in flavanone

Studies of the genesis of the [M ? H]⁺ ion in flavanone and 2′-hydroxychalcone, performed with the aid of metastable decompositions and deuterium labelling, allow new structural notations to be postulated for the [M ? H]+ ions, which in turn provide evidence for the pathways in the [M ? H – ketene]+ fragmentation routes for these compounds.