A simple template to calculate Relative Retention Times (RRT) (OpenLAB CDS Intelligent reporting)

Document created by agilent Employee on Mar 24, 2016Last modified by agilent Employee on Mar 24, 2016
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OpenLAB CDS ChemStation C.01.05 or higher offers a new calibration table feature to set RRT reference peaks and the results are stored in the ACAML result files and can be reported with OpenLAB Intelligent Reporter. (see on-line help for Calibration Table Options )


Older ChemStation revisions may use the attached report template that was developed with OpenLAB CDS ChemStation C.01.01. It can be used to create single run ESTD reports with Relative Retention Times (RRT). The reference peak identification uses a ChemStation compound related custom field.

Detailed instructions are included in the template and in the section below.


The relative retention time is calculated by dividing the net retention time of a peak by the net retention time of the reference peak. The net retention time gets calculated by substracting the retention time of a unretained compound (hold-up time) from the measured retention time. In this template the hold-up time is set by the retention time of the very first integrated peak.
The method's integration events need to be adjusted to suppress integration of peaks prior to the unretained compound.

Use a compound related custom field in the ChemStation acquisition method to define the reference peak:
In order to use compound related custom fields, the method need to have a calibration table containing at least the reference peak. The peak doesn't necessarily need to be calibrated.

In Method and Run Control view:

  • Methods > Custom Fields setup
  • In the 'Compound Custom Fields' press the PLUS button to add a new custom field
  • Add "RRT Ref" as a custom field name, but don't make it 'mandatory' nor specify a default value.
  • save the method

To use the custom fields in a sequence:

  • set up a new sequence table with the previously created method
  • press the 'Custom fields button' and switch to the compound custom fields tab. Select the reference compound and fill all custom fields of this compound with 'y' or anything else.  Leave the custom fields of the non-reference compounds empty.
  • save the sequence and execute it


(originally posted in OpenLAB Forum: https://zohodiscussions.com/openlabcdsforum#Topic/68030000000132003

2014 September 10 by betrich)