Welcome to GC-AutoFit

GC-AutoFit is a web application that automatically identifies and quantifies metabolites using Gas Chromatography Mass Spectrometry (GC-MS) spectra. For optimal GC-AutoFit performance, the query GC-MS spectra should be prepared according to the instructions (How to collect GC-MS Spectra for GC-AutoFit). GC-AutoFit currently accepts .CDF and .mzXML file formats. It uses alkane standards to calculate the retention index (RI) of each peak in the sample. The extracted EI-MS spectra from each peak, along with the RIs, are then compared to reference spectra (RIs and EI-MS) in the specified library to identify and quantify the compounds. The inclusion of blank spectra is optional, however, it is useful for removing noise effects from the query spectra. Extensive testing shows that GC-AutoFit meets or exceeds the performance of highly trained human experts.

GC-AutoFit Analysis


To analyze GC-MS spectra with GC-AutoFit you must provide information on the biofluid being analyzed and the spectral files in .CDF or .mzXML format. Upto 30 spectra are recommended to analyze in one submission.

Submit your own mixture:

  1. GC-AutoFit works with urine and your own custom libraries.
  2. Compound must be present in selected library.
  3. All spectral files must be .CDF or .mzXML. Up to 30 samples can be submitted.

    The ZIP file must contain an alkane standards spectrum (e.g. Alkane.mzXML, ALKstd.mzXML), an optional blank spectrum (e.g. Blank.mzXML, Blk.mzXML) and at least one sample spectrum. All the spectral files must be .CDF or .mzXML. Up to 30 samples can be submitted.

  4. An integer between 0 - 999 but somewhere between 400 - 600 is recommended.

OR, run one of our examples: