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Topics - kraigkraig

1
XCMS / visualizing SNRthresh
Hi,

Recently I have been toying around with setting a sensible signal-to-noise threshold. I have a data set where the concentration of the samples was excessive.  The chemical noise of these samples is high, but the data seems usable (I hope). I would like to set the filter in such a way that reliable peaks are conserved and noise is reduced, but I'm not sure of the best way forward. 

Is there way to visualize the outcome of the SNR-threshold on the raw data on a known peak?  Is there a good way to set this criteria in a non-arbitrary manner?  I may be missing some more obvious or graceful solution, so I would appreciate any input!

Cheers,

Kraig Worrall    :|
2
XCMS Online / snrthresh & chromatogram cropping
Hi,

First time poster here! I have two questions about XCMS online.  :?:

First, is it possible to adjust the signal-to-noise threshold with XCMS online?

Is it possible for me to crop sections of the chromatogram so that signals from unwanted regions will not be tabulated?, e.g. first minute and column wash out.

Thanks,

Kraig Worrall
Agriculture and Agri-foods Canada