Display time intervals (peak time windows) in chromatograms?

[stuart]

It would be useful to be able to see the peak time window shown over the chromatogram. This would be useful:
i) to show If the windows selected are appropriate (or even sensible!)
ii) to show if the retention times have changed relative to the times in the calbraion table (eg either the chromatographic conditions have changed a little, or the 'enable retention time change' has been left in the default on setting)
iii) Because of how Clarity handles overlapping time windows (taking the overlap and dividing it by two, half for each peak). It is good, because it eliminates the problems of overlapping windows, such as a peak in two different time windows, but it is possible that the resultant time window is not quite what was intended.

Personally, I would also like to be able to specify how the data system deals with multiple peaks in the same time window. ie take the first peak, the biggest peak or the peak nearest to the specified retention time. It is really important to be sure than an unknown or a small peak appearing in the time window is not identified as the target analyte. I recommend everyone considers using the Minimum height setting to eliminate small peaks causing problems in this respect (careful to use minimum height not minimum area). If this suggestion were to be implemented, I would envisage it being under calibration settings and not a peak table column.

Internal issue tracking ID: 62048

[Daniel Mentlik]

Dear Stuart,
please note the setting for selection of peaks in the time windows is already present in Clarity:

The Peak Selection column is hidden by default, but can be displayed by using the Setup Columns... command from the Compound Table context menu in the Calibration window. I have done some testing today and the setting is not as straightforward as I would expect, so I have started a new issue (ISS59669), but it works.

As for the rest of the suggestion, would you be interested in viewing such intervals in Chromatogram window or in the Calibration window (or both)? The introduction of the feature might be more simple for the Calibration window, but part of the usefulness (e.g. seeing right away why the peak in the chromatogram of the sample is not identified/quantified) would not be that straightforward.

[stuart]

If it were possible, I would like to be able to apply the time windows (maybe displayed like error bars sideways) to the chromatogram window, so that if retention times change, it becomes obvious if the peaks are falling out of their prescribed time windows. But the major issue is to show if time windows overlap.

I was pleased to see that it is possible to specify how to deal with multiple peaks in the same time window. I didn't know that was now available, probably because it is so well secreted away, but that is a good addition to Clarity.

[Daniel Mentlik]

I have started a suggestion for this feature, generally similar behavior is available in the Chromatogram window of the MS extension (the background subtraction intervals and mean spectrum calculation interval are displayed by vertical lines overlayed with the chromatogram.