Fig. 1.

LC/ESI/MS/MS spectra and selected ion monitoring of dilysyl-MDA cross-link, and structure of product ions. The [MH]⁺ ions of dilysyl-MDA cross-link (m/z 329) were subjected to collision-induced dissociation (CID). The product ions were scanned from m/z 50 to 350. The spectra recorded at −15 (upper spectrum) and −28 eV (lower spectrum) are shown with the proposed structures of the major fragment ions. The corresponding m/z values for the internal standard (IS) are presented in parentheses.