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Topic: Multiple features for narrow RT range (Read 839 times) previous topic - next topic

Multiple features for narrow RT range

Hello there,

We have a question in regards to XCMS feature selection.

Upon preprocessing of QTOF data XCMS spits out a results table that shows multiple features across very narrow bands of RT ranges.
For example 30 different features (though often closely related ones) at a RT of 4.3 minutes. Another 15 for 4.5 minutes etc...

We've tried various preprocessing settings, but this doesn't change feature selection dramatically.

What could be going wrong?
Thanks.

Re: Multiple features for narrow RT range

Reply #1
Are you talking about adducts and fragments? XCMS does not attempt to give you one feature per compound but one feature per ion.

CAMERA would be the standard tool to try to group ions originating from the same compound. There is however no consensus on how to statistically treat/merge those groups.
Blog: stanstrup.github.io

Re: Multiple features for narrow RT range

Reply #2
Excellent. That actually explains the EIC and TIC chromatograms versus the feature selection.
Thanks  ;D