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Comparisons with Retention Index

GC-LC CONCORDANCE allows to directly compare chromatograms with Kovats retention Indices in a single operation and by an internal or external calibration.

It’s now possible to keep the precision of the index calculated on the sample, without the constraint of resetting the instrument by regular injection of alkanes. Indeed, retention time shifts on the sample is recalculated with the precise indices kept on the reference.

A specific mathematical algorithm allows to recalculate Kovats retention indices on the sample without needing to recalibrate the instrument.


The example below shows two chromatograms (between 500 and 600 peaks) of two oil products from two different countries (different devices, different PONA columns) but using the same analytical method.

No mathematical treatment could compensate automatically the retention time variability of these 2 chromatograms.

However, after a conversion into retention indices, GC-LC CONCORDANCE is able to match these two chromatograms. It calculates indices variations of the products in between alkanes Cn and Cn+1 (C1-C120). Then it can put together family of products and a quantification of chemical components with a very good precision.

Traditional methods using multiple windows can not guarantee such a precision. Moreover without GC-LC CONCORDANCE, you need complicated and long recalibrations and changes of columns!


petroleum product chromatogram
petroleum chromatographic fingerprints comparisons