An integrated method for spectrum extraction and compound identification from gas chromatography/mass spectrometry data

A method is presented for extracting individual component spectra from gas chromatography/mass spectrometry (GC/MS) data files and then using these sp ectra to identify target compounds by matching spectra in a reference Libra ry. It extends a published "model peak" approach which uses selected ion ch romatograms as models for component shape. On the basis of this shape, indi vidual mass spectral peak abundance profiles are extracted to produce a "pu rified" spectrum. In the present work, ion-counting noise is explicitly tre ated and a number of characteristic features of GC/MS data are taken into a ccount. This allows spectrum extraction to be reliably performed down to ve ry low signal levels and for overlapping components. A spectrum match facto r for compound identification is developed that incorporates a number of ne w corrections, some of which employ information derived from chromatographi c behavior. Test results suggest that the ability of this system to identif y compounds is comparable to that of conventional analysis.