Comparing Chromatograms
Normalizing Chromatograms

For a sensible comparison of different chromatograms, often a common reference point is chosen for the overlaid chromatograms (see Overlay). The chromatograms are normalized. As the default, the Retention Time is used for the normalization, that is, all chromatograms are arranged so that their start points match (t = 0).

Alternatively, chromatograms can use a common peak as their reference point.

• Select Decoration on the context menu and open the Comparison tab page.

• Select the reference peak from the At Peak list box.

• Select Shift if this is to be performed independently from the length of the chromatogram.

• Select Stretch if the chromatograms are to be stretched or compressed in x-direction, so that there is a time scaling in all chromatograms. The stretch 0 to 1min (or n min) has the same length for all chromatograms.

• Enable the Normalize Signal check box if the height of the selected chromatogram peak should match in addition. Depending on how much the reference peak must be stretched or compressed, all other peaks in the chromatogram are also stretched or compressed. This enables amount estimation for the same peaks from different chromatograms. This option is not available in the Stack view.

Chromeleon supports several actions for overlaying chromatograms. For an overview, refer to  Comparing Chromatograms.