MS/MS fragmentation maps of doubly deprotonated
wild type E. coli lipid A (Mr = 1797.2)
using (A) CID, (B) HCD, and (C) UVPD-MS. Each cleavage site is numbered,
and the fragment ions arising from each cleavage site is listed. Those
fragment ions that require multiple cleavages are listed next to each
cleavage site. Red cleavages are only seen using UVPD-MS. The positions
of the 2, 2′, 3, and 3′ carbons and the GlcN I and GlcNII
are labeled in part A.