What does reprocessing mean on a chromatogram?

What does reprocessing mean on a chromatogram?

Reprocessing of the data generally means that after the data is acquired, the chromatograms are subjected to some sort of manipulation, meaning data processing. I know that to defense attorneys that when they read the word “manipulation” that is like nails on a chalk board to them inherently. It is a justified alert, but certainly is not an automatic condemnation. We need to look at the method and the integration and data processing procedures.

It could be an unintuitive, error prone and repetitive task or it could be something that is well defined and justified and utterly scientific. It is for us to discover.


Some programs like TotalChrom allow the user to Batch reprocess the information so that every chromatogram is subjected to the same manipulation equally. All programs allow for manipulation on an individual chromatogram (remember what Josh does in the integration talk in the GC class). Some programs like ChemStation allow the user to click one button to “AutoIntegrate” a specific chromatogram.


It all depends on how the reprocessing is used. It can effect quantitation and in the extreme even qualitative identification.

The bottom line is that if there is reprocessing, we have to make very sure that the calibrators are subjected to the same reprocessing events as the unknowns. If they are different, then the results may be different.

For additional information about integration and reprocessing of data in a GC system, please read:

The case for raw data: “Integration” in Gas Chromatography: How to make an innocent person guilty in a DUI case by manipulating the software

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