IsoCor: Isotope Correction for mass spectrometry labeling experiments

Welcome to IsoCor documentation!


IsoCor is a scientific software dedicated to the correction of mass spectrometry (MS) data for naturally occuring isotopes. IsoCor corrects raw MS data (mass fractions) for naturally-occurring isotopes of all elements and purity of the isotopic tracer. The output of IsoCor is the isotopologue distribution (i.e. the relative fractions of molecular entities differing only in the number of isotopic substitutions of the tracer) of the molecule. IsoCor also calculates the mean enrichment (i.e. the mean isotopic content in the molecule) in metabolites.

It is one of the routine tools that we use at the MetaSys team and MetaToul platform in isotopic studies of metabolic systems.

The code is open-source, and available on GitHub under a GPLv3 license.

This documentation is available on Read the Docs ( and can be downloaded as a PDF file.

Key features

  • correction of naturally occuring isotopes, both for non-tracer and tracer elements,
  • correction of tracer purity,
  • shipped as a library with both a graphical and command line interface,
  • mass-spectrometer and resolution agnostic,
  • can be applied to singly- and multiply-charged ions
  • can be used with any tracer element (having two or more isotopes)
  • account for the contribution of derivatization steps (if any),
  • generate InChIs of isotopically-resolved (tracer) isotopologues,
  • open-source, free and easy to install everywhere where Python 3 and pip run,
  • biologist-friendly.

See also

We strongly encourage you to read the Tutorials before using IsoCor.