Mass spectrometric comparison of GC-MS and LC-MS analyses

Paul Boughton

Real life samples with complex matrices have complex chromatograms that make the evaluation for presence of contamination or residual components a difficult and time consuming task. The recently developed Compare tool of the mass spectra evaluation software MassLib finds both qualitative and quantitative differences between two GC-MS or LC-MS analyses and presents the results graphically and in tabular form.
The only prerequisite is that the two analyses have been acquired under chromatographically comparable conditions.
For an efficient analyses compare tool several features are required which all are provided in the MassLib software. A peak finder algorithm must be capable of finding component spectra even if coelutions and variable background is present. It must be possible to compare the two analyses based on retention index scaling and on absolute intensities. The spectral comparison must reliably recognise that a spectrum is contained in the comparison spectrum even if not readily visible.
MassLib’s SISCOM algorithm (Search for Identical or Similar COMpounds) is better suited for this task than algorithms that are optimised for determination of spectral identity.

MSP Kofel is based in Zollikofen, Switzerland. www.msp.ch

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