Analytical methods for Challenge13 Sample: The compound is a natural product derivative. The molecular formula of the precursor [M+H]+ is C17H31N2O5. Precursor ion type: [M+H]+ Molecular formula of precursor ion: C17H31N2O5 Instrument: AXIMA QIT (Shimadzu) Ion source: MALDI, positive ion mode Matrix: 3,5-Dihydroxybenzoic acid (DHB) / 50% MeOH with 0.1% Trifluoroacetic acid (TFA) CID conditions: 200-500-650 (Argon) Shot/laster: 10 shots per profile / 882 profiles were accumulated.