Figure 4
From: Application of multiple statistical tests to enhance mass spectrometry-based biomarker discovery
Peak alignment across spectra. Representative spectra from the high performance prOTOF mass spectrometer are shown before (top panel, 84 spectra) and after (bottom panel, 68 spectra) data preprocessing. Data preprocessing entailed removal of outlying spectra and normalization of signal intensity to the average TIC. Shown in the insets are the enlarged view of peak at m/z = 2021 which has a mass accuracy of < 10 ppm, rendering spectrum-to-spectrum alignment unnecessary. Each spectrum is plotted in a different color through arbitrary assignment.