Retention time update

Update → Selection → Retention time writes expected retention times from the samples in the focused grid. Update → All analytes → Retention time uses every analyte. The dialog title is Update method RT.

The preview lists analytes that have a peak time. If none do, Quanto reports that no method retention times can be updated.

What is written

For each analyte, the new expected RT is the average of the selected peak times on the samples in the preview. The peak is the one on the selected result’s signal. Times that are not positive are ignored. One sample contributes its peak time. Several samples contribute the mean. This is the peak time (the integrated apex / center), not a separate “average the whole peak” model.

After the times are written, time-reference correction is queued so relative retention that depends on RT-reference analytes is updated. The ISTD link is not what shifts the expected RT. The ISTD normalizes response. Relative RT follows the time-reference analytes when the method has them.

The time window is not changed. A new expected RT still uses the existing window (default 0.5 minutes). See Peak identification.

Which analytes and quants

Selection is the analytes and samples of the grid you opened the command from. All analytes is every analyte, still limited to the samples that are selected for the update. In the preview, Update selected writes the analytes you highlight. Update all writes the preview set. If the dialog was opened for a subset, Update all stays inside that subset.

Retention time is stored on the analyte, so every quant of that analyte shares the new expected RT. Qualifier windows move with it. Quant-specific curves are not given different expected times by this command.

Acquisition key

The analyte’s acquisition key is overwritten only when every sample that contributed a peak time shares one effective key. If the samples span two keys, the key is left as it was and the averaged time is still written. See Acquisition keys.

Undo

Edit → Undo undoes review actions (approve, undo approve, zero, or undo manual integration). It does not restore the previous expected RT. Save the method before a large update if you want a file to return to.

Related commands: Updating qualifier ratios and Spectra update.