Flow-modulated comprehensive two-dimensional gas chromatography combined with a vacuum ultraviolet detector for the analysis of complex mixtures

The present paper is focused on the use of a vacuum ultraviolet absorption spectrometer (VUV) forgas chromatography (GC), within the context of flow modulated comprehensive two-dimensional gaschromatography (FM GC × GC). The features of the VUV detector were evaluated through the analysisof petrochemical and fatty acids samples. Besides responding in a predictable fashion via Beer’s lawprinciples, the detector provides additional spectroscopic information for qualitative analysis. Virtuallyall chemical species absorb and have unique gas phase absorption features in the 120–240 nm wavelengthrange monitored. The VUV detector can acquire up to 90 full range absorption spectra per second, allowingits coupling with comprehensive two-dimensional gas chromatography. This recent form of detectioncan address specific limitations related to mass spectrometry (e.g., identification of isobaric and isomericspecies with very similar mass spectra or labile chemical compounds), and it is also able to deconvoluteco-eluting peaks. Moreover, it is possible to exploit a pseudo-absolute quantitation of analytes based onpre-recorded absorption cross-sections for target analytes, without the need for traditional calibration.Using this and the other features of the detector, particular attention was devoted to the suitability ofthe FM GC × GC-VUV system toward qualitative and quantitative analysis of bio-diesel fuel and differentkinds of fatty acids. Satisfactory results were obtained in terms of tailing factor (1.1), asymmetry factor (1.1), and similarity(average value 97%), for the FAMEs mixtures analysis.