MS/MS Ion series of unmodified and adduct-modified model peptides by naphthalene epoxide (NO) and naphthalene diol epoxide (NDO) at pH 8.5.

Product ion spectra for adducted peptides were indistinguishable between both pH conditions; more products were observed at pH 8.5 therefore ions series for the products at this pH was given.aObserved signals assigned as b- or y- ions are listed. The bold b- and y- ions represent ions modified by the naphthalene epoxides.bReference to detailed supplemental spectra corresponding to the appropriate ion series.cThe modifications are naphthalene epoxide (mass +144.06 Da).dIn the fragment ion signals, X represents the mass of the adduct.eThe modifications are naphthalene diol epoxide (mass +178.06 Da).f[DYKDDDDK + NO] was observed in the dehydrated form; fragmentation confirmed the adduct.