Application of comprehensive two dimensional gas chromatographyto wine analysis

[摘要] ENGLISH ABSTRACT: This study focused on the potential of comprehensive two-dimensional gaschromatography coupled to time-of-flight mass spectrometry (GC×GC-TOF-MS) forthe improved analysis of volatile wine constituents. Solid phase microextraction(SPME) in combination with GC×GC-TOF-MS was successfully used for the detailedinvestigation of the impact of three commercial Oenococcus oeni lactic acid bacteria(LAB) strains on the volatile composition of Pinotage wines subjected to malolacticfermentation (MLF). Due to increased separation power and enhanced sensitivityobtained by using two orthogonal separations coupled with the structural informationprovided by deconvoluted TOF-MS spectra, GC×GC-TOF-MS allowed for theidentification and semi-quantitative analysis of much larger numbers of compoundscompared to previous studies applying one-dimensional gas chromatography. Thecombination of univariate and multivariate statistical assessment was used as apowerful tool for data interpretation. The obtained results contribute significantly tothe understanding of the impact of MLF on the volatile composition of Pinotage wineSome compounds have been linked to MLF for the first time.Moreover, the impact of these commercial starter cultures on the composition ofvolatile sulfur and nitrogen compounds in the same wines was studied byone-dimensional gas chromatographic methods with headspace injection and solidsupported liquid-liquid extraction together with sulfur selective detection and tandemmass spectrometry. This study demonstrated also for the time, the impact of MLF onthe composition of volatile sulfur and nitrogen compounds in Pinotage wine.GC×GC-TOF-MS was further used for the evaluation of the suitability of a new phasefor stir bar sorptive extraction (SBSE) analysis of wine volatiles. Despite instrumentalcomplications, beneficial extraction properties of the new stir bar phase for especiallymore polar compounds could be demonstrated. In addition, the extraction ability ofthis novel phase was evaluated for the analysis of selected thiazoles in wine usingheart-cutting two dimensional gas chromatography in combination with nitrogenselective detection. Advantageous extraction performance of the new stir bar phasecompared to a conventional polydimethylsiloxane (PDMS) phase for the determinedthiazoles was demonstrated.

[发布机构] Stellenbosch University