Diagram of two peak sets. Peaks in a sample peak set SP match with peaks in a reference peak set RP. SP is composed of detected TIC peaks, i.e, capital P's, in which individual EIC peaks, p's, up to five, are arranged in descending order of their signal-to-noise ratios. Note that RP is a peak set composed of "inferred TIC" peaks since individual EIC peaks, q's, are first identified by using the mz values of SP and then are grouped into a TIC peak. This also illustrates the matching of TIC peak P1 to Q1, but of P2 to Q3 because, in the latter case, either peak Q2 had no EIC component (q21and q22) with a matching mz value, or the spectra of P2 and Q2 were insufficiently correlated, whereas Q3 met both of these conditions, with q32 having matching mz.