In we observed that this performs well for the annotation of features. However, if the intensities I i represent a concentration profile that should be integrated over time, this change poses a problem. In Figure we show an example. We suppose an EOF arriving at t EOF = 10, a marker with t A = 1 and effective mobility µ A = 100, and no ramp time. We then place two peaks with similar widths σ 1 = 0.2 and σ 2 = 0.25 and exactly the same area A 1 = A 2 = 1, at times t 1 = 2.5 and t 2 = 7. Because of the nonlinearity of the t → µ transformation, the peak areas are completely changed. Although gaussian-like peaks will remain essentially gaussian as long as they do not overlap the EOF (whatever distortion may be introduced by the transformation is negligible next to the inherent variations in CE peak shapes, as we will see), peak widths are changed notably. This was already observed in , and the necessary correction was derived in for the simple case of (15). We will redo the calculation to include the ramp factor and the secondary marker. Essentially, having a closed formula such as for µ(t) allows us to compute a correction factor. In the limit of a continuous intensity profile I(t), the area under the curve of a peak in the electropherogram is given by