The application of GC and GCxGC in combination with state-of-the-art and novel detection systems for the analysis of petrochemical matrices

Gas chromatography (GC), mass spectrometry and optical spectroscopy are standard techniques for the analysis of petrochemical matrices and within last decade also comprehensive two-dimensional gas chromatography (GCxGC) did become a key technology in this field. The application of GC and GCxGC in hyphenation with mass spectrometry as well as spectroscopic techniques allow unprecedented qualitative as well as quantitative investigation of these matrices. However, the analysis of high boiling matrices remains challenging because of the physical limitation of gas chromatography but also because of the increasing chemical complexity of matrix. The lecture will cover different state-of-the-art as well as novel approaches, where GC and GCxGC will be combined with thermal introduction systems and/or very selective detection systems to get a deeper insight in such complex matrices. 

Middle distillates and blends with an equal boiling point range could be analyzed almost comprehensively by GCxGC with an appropriate selective detection system like fast time-of-flight mass spectrometry (TOFMS) or vacuum ultraviolet spectroscopy (VUV). Due to the selectivity of the hyphenated systems also very detailed quantitative information could be derived for more than 99% (m/m) of the introduced matrix. Higher boiling points require an adaption of the gas chromatographic methodology and, as compensation for the lost chromatographic separation power, more selective detection systems. Mass spectrometer with very high resolving power and mass accuracy are suited for such approaches. While Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS) with a sophisticated algorithm for the removal of ionization artifact could be hyphenated to one dimensional gas chromatography, fast and high resolution time-of-flight mass spectrometry complies with the needs of GCxGC. Both techniques allow the link between chromatographic and elemental analysis. In addition standard techniques like high temperature simulated distillation could be extended to their two- dimensional equivalent for a qualitative and quantitative analysis of petrochemical matrices up to the limits of GC. 

Above the temperature limit of GC(xGC) the frontend could be modified and hyphenated to thermal analysis. A direct link between thermal gravimetry (TG) and/or differential scanning calorimetry (DSC) with GC and appropriate detection system allows a profound analysis of the evolved gases. Physical properties could be derived from TG and DSC while the evolved gases are separated by boiling point and the selectivity of the GC. MS detection with an appropriate ionization method like single photon and resonance-enhanced multiphoton ionization add an additional selective dimension.