Enhanced MALDI-TOF MS Analysis of Phosphopeptides Using an Optimized DHAP/DAHC Matrix

Figure 2

Top two views show the MALDI samples containing the phosphopeptide pT using (a) DHAP/DAHC matrix and (b) DHB/PA matrix. The two center pictures show the signal intensities of the phosphopeptides pT (250 fmol on target) measured with (c) DHAP/DAHC matrix and (d) DHB/PA matrix. The images only show a cut at signal intensity of 400 mv for clarity. The positions with signal intensities above 400 mv are indicated in purple. The bottom row (e) shows a schematic of the data acquisition method for investigating sample homogeneity of the matrix. In total, 196 positions were selected as a 14 × 14 spots array to cover the crystalline matrix/analyte layer, and 50 profiles (5 shots per profiles) were accumulated at each position.

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