All data vs Top 1% of data. (a) The comparison of the total ion chromatograms of all and top 1% of data. The abscissa and ordinate axes correspond to the retention times and ion intensity, respectively. The total ion chromatograms of all data and top 1% of data were plotted as black and red solid lines, respectively. (b) Two dimensional map (m/z vs retention times). Top 1% of data are plotted as red points.