ABSTRACT
Two mass spectra are available in this case. ESI mass spectra allows to identify the molecular ion4 and, subsequently, the molecular mass of the compound. Unfortunately, due to the fast fragmentation of molecular ions under high-energy EI conditions, in many EI-MS spectra, the molecular ion peak is too small to be detected. In this ESI-MS spectrum, we can easily observe the peaks corresponding to the protonated molecular ion 4 [MH]+, m/z 76, and the [M + Na]+ adduct, m/z 98. However, because of the absence of molecular fragmentation, little or no structural information is available from this technique - just the opposite of what EI-MS provides. The odd molecular mass of the molecular ion (m/z = 75) indicates that we presumably have a nitrogen compound. A Dm/z of 18 mass units between
