The peaks were then extracted from the raw electropherograms, and from the mobilograms under different types of area correction. The conversion to mobilities was done using the full two-marker formula as in the previous subsection. For each compound and injection volume, we computed the coefficient of variation over the six replicates of the corresponding peak areas. Figure our case (×t 2 , following Table ) the CVs remain the same between the peaks in the electropherograms and the ones in the mobilograms (∼ 5%). If the wrong correction is made, by assuming that the ESI operates in concentration mode, leading to a factor of ×t, the peak areas show about three times more variability. It is only made worse by making no correction whatsoever.