Graphical representation of the `Find best region' pop-up panel derived from the pairwise P-value analysis with Blanks comparison of the lysozyme data of Fig. 2 and Fig. S3 in the supporting information (see Fig. S4 in the supporting information for a screenshot of the actual panel). On the left y axis, red bars indicate the average red cluster size for the chosen window size (here 20 frames) of the actual chromatogram as a function of each starting frame number, compared with the average Blanks values + 1 s.d. (green solid and dotted horizontal lines, respectively) computed for all possible windows of the same number of frames; cyan and white bars represent windows with an average within +1 s.d. of the Blanks, with the white bars being the lowest (equal) averages recorded. On the right y axis, the orange lines indicate the average integrated intensity ± 1 s.d. for each of the 20-frame windows analyzed on the actual chromatogram, as a function of each starting frame number; the magenta horizontal line indicates the zero expected intensity if no capillary fouling or other phenomena such as drifting have occurred.