GC×GC-TOFMS

Two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (Leco Pegasus instruments). The first GC column separates by boiling point; a cryogenic modulator re-focuses all compounds onto a short second column that separates by polarity. The resulting 2D chromatogram resolves hopane and sterane clusters from petroleum matrix co-elutions that confound standard GC-MS.