Align chromatograms from multiple detectors

If you use different detectors (for example, UV and MS detectors), each detector may see the analyte or analytes at a slightly different time. To reduce the delay time, minimize the connection volume between the detectors.

To take care of the remaining delay time, align the signals in the software.

Privileges

• OpenLab CDS: Method Development > Edit signal parameters
  Privileges are configured in the Control Panel.

Prerequisites

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

1. In the General > Signals node (Alignment tab) 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. In general, it is best to choose the latest eluting peak that is present in all selected detectors.

3. Click Calculate delay from RT.

   

4. Save the method.

5. Reprocess the data.

   All spectra and EICs are deleted. EICs and automatically extracted spectra are re-generated with the updated retention time info.

   Using a delay will affect calculations based on the retention time, or based on signals from multiple detectors. For example:

   • Sample purity calculation from a UV signal

   • Extraction of MS spectra from non-MS peaks

NOTE

Values in the processing method, such as the expected retention time, are not changed automatically. If required, adjust them manually. See Shift the expected retention times of all compounds.

See Also

If you use qualifiers, update qualifier responses after aligning signals..

If you installed the 2D-LC Add-on: See Align signals over two dimensions in the 2D-LC Analysis Add-on Software help.