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EuracBiomedicalResearch / lcms-standards

Measurements of standard compounds in LC/MS setups and configurations at Eurac Research
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Match MS2 spectra independent of the adduct #90

Closed jorainer closed 2 years ago

jorainer commented 2 years ago

Maybe stupid idea (and eventually being already covered by neutral loss spectra): assume we have a feature for a [M+Na]+ of an ion. MS2 spectra for such an ion might (will) not match a reference [M+H]+ ion of the same compound.

What if we subtract the ion part from the m/z values of both spectra? i.e. subtract mass of Na from all m/z values of the experimental MS2 spectra and the mass of H from the m/z values of the reference spectrum. The MS2 spectra will no longer be m/z against intensity but mass against intensity.

Maybe worth a try... although, as said, might be the same result we get from a neutral loss spectrum (without having to know which adducts we have).

jorainer commented 2 years ago

could be easily be done using the mz2mass function from MetaboCoreUtils: generate mass spectra first and then comparing these.

jorainer commented 2 years ago

Did not really help. Results should actually be the same as calculating the neutral loss spectrum by subtracting the precursor m/z (only avoiding negative m/z values).