FIGURE 7.

Negative ion vMALDI-LIT mass spectra of HF-treated wild-type O-LPS. After HF treatment, the predominant deprotonated monoisotopic mass observed in the wild-type sample was at m/z 2136 (supplemental Fig. S10). MALDI-MSⁿ analyses were performed on the parent ion at m/z 2136 (A). Fragment ions at m/z 1208 and 892 were sequentially fragmented to determine the composition of the parent mass as shown in B and C, respectively. Masses labeled with an asterisk designate major masses minus water or CO₂.