As illustrated in Fig 4B and 4C, respectively, the loss of an amide group was corroborated to m/z 152.035 for 2,3-dihydroxybenzamide as indicated by the fragment ion at m/z 109.03 [C 6 H 5 O 2 ] and m/z 178.015 for benadrostin that gave a fragment ion at m/z 137.02 [C 7 H 5 O 3 ].