Recall that the purpose of transforming migration times into effective mobilities is to allow peak-picking software to have a robust identifying parameter (the mobility of the compound) to annotate features extracted from electropherograms. The obvious approach, as implemented in , is to use formula or to map t → µ(t). An electropherogram is measured as a list of couples (t i , I i ) of times t i and intensities/counts I i . Therefore the mobilogram should be computed by