A rapid routine to correct for skewing in gas chromatography/mass spectrometry

In gas chromatography/mass spectrometry (GC/MS) with magnetic instruments and quadrupoles, skewed (‘tilted’) spectra are obtained owing to the changes in analyte concentrations in the source of the mass spectrometer during the measurements of one scan. Skewing depends on the ratio of cycle time to GC peak width. The combination of capillary chromatography with magnetic instruments often results in skewing to an extent that both manual and automatic processing of GC/MS data are seriously hampered. An algorithm is described to correct for this effect. The results of the unskew algorithm are evaluated on real GC/MS data.