Align chromatograms containing fractions

If you use different detectors to trigger LC fractions, each detector sees the fractions of interest at a slightly different time, and fraction annotations appear to be shifted in the Chromatograms window. Use the following procedure to align the annotations and signals.

Prerequisites

• To be able to carry out the procedure as described, you need the privilege Processing Method > Edit signal parameters. Privileges are configured in the Control Panel.

• If the project enforces method approval, the method status must be Generic. For details, see Method approval.

1. In the General > Signals node of the processing method, select the Use delay check boxes for the relevant detectors.

The list includes all detectors used in the loaded data.

2. Change the RT (min) values. Enter the delay time for each selected detector.

To get the delay time: For example, select the corresponding signal in the injection tree, and check the Fraction results window. Use the start time of a specific fraction as a delay time in the Alignment table.

3. Click Calculate delay from RT.



4. Save the method.

5. Reprocess the data.

Using a delay will affect calculations based on the retention time or on multiple signals.

6. In the Chromatograms window, click to link the x-axes of all graphs.