Analysis of fossil‐fuel fractions by on‐line coupled microcolumn HPLC capillary column GC‐MS

A multidimensional LC‐GC‐MS system was developed and used to analyze complex fossil‐fuel samples. The electron‐acceptor stationary phase, 5 μm 2,4‐dinitrophenylmercaptopropylsilica, was packed into a 0.32‐mm × 350‐mm microcapillary liquid chromatography (μLC) column. Aromatic fractions eluted from the μLC system at 12 μL/min and were diverted to the gas chromatograph mass spectrometer (GC‐MS) by a ten‐port switching valve with 50 and 7.6‐μL loops. Concurrent cosolvent evaporation occurred in a 0.32‐mm × 3‐m precolumn ahead of a 0.25‐mm × 30‐m DB‐5 analytical column. Solvent vapors exited through an open‐split interface. The utility of the μLC‐GC‐MS system was demonstrated through the analyses of solvent refined coal, kerosene, and crude oil.