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XiaoyangSu / AccuCor

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When I correct natural abundance,I have a question about result, and I don't know why? #14

Closed nyj123 closed 3 years ago

nyj123 commented 3 years ago

for example, this is my raw data image and my result like this image and I don't kmow why lactate m+3 abundance will be more. I use U-C13glutamine tracer.

Thanks very much!

nyj123 commented 3 years ago

And I calculate by the formula image, Only m+3,I think it has something wrong

Thanks a lot

XiaoyangSu commented 3 years ago

The lactate M+3 goes up after correction is normal. This is because the tracers typically have 99% isotope purity (99% 13C and 1% natural carbon). I assume you are using the 13C5-glutamine from Cambridge Isotope Laboratory (see https://shop.isotope.com/productdetails.aspx?itemno=CLM-1822-H-PK), which is 99% 13C. If your tracer is 100% pure, you can change the tracer purity parameter (purity=1). Please note this is the isotope purity, not chemical purity. Meanwhile, our correction isn't sequential from M+0 to M+n. We use non-negative least squares regression to correct all the labeled fractions together. Please see our Anal Chem paper for more details.

nyj123 commented 3 years ago

Oh,I get it! Thanks a lot!