Request features: flagging (or solving?) saturated features

[lfnothias]

Hi,

Saturation of the detector in mass spectrometry is quite common in metabolomic. Obviously, these saturated MS1 or MS2 features cannot be compared properly between samples. Decreasing the sample concentration allows to avoid saturation of most abundant features, but will lead into a loss of sensitivity regarding the smaller intensity features, that deserves to be investigated as much as the most abundant ones.

So it would be great to tackle this matter, and I can see two options:

• The easiest solution, would be to indicated saturated ions in the output table of Optimus. Saturated peaks can be spotted easily by looking at their top-flattened shape of the monoisotopic ion, but also by looking at aberrant change in the isotopologue ratio.
• An idea to overcome this saturation issue, could be to use the 13C isotopologue (m/z +1) as a proxy to estimate the intensity of saturated monoisotopic ion across various samples. I know that Optimus contains an OpenMS option that pool detected isotopologues for a MS1 feature. But I think it takes into account only the m/z +1 (and/or +2), only if, the isotopologue ratio match a "natural" profil for metabolite. So that doesnt solve the problem here.

I take the chance to express how fantastic Optimus workflow is ! Thanks guys for sharing it with the community.

Louis-Félix