Static Headspace Analysis Using Low-Pressure Gas Chromatography and Mass Spectrometry, Application to Determining Multiple Partition Coefficients: A Practical Tool for Understanding Red Wine Fruity Volatile Perception and the Sensory Impact of Higher Alcohols.

To evaluate the partition coefficients of volatiles between the liquid and gas phases, an analytical method was developed and optimized using static headspace analysis and low-pressure injection gas chromatography coupled to mass spectrometry (SHS-LP-GC/MS). Two different types of analytical columns were coupled for low-pressure chromatography injection: a narrow restriction microbore column on the inlet side and a mega-bore column on the mass spectrometer side. Coupling these two columns and static headspace analysis to gas chromatography and mass spectrometry resulted in a simple, fast, sensitive, and accurate approach. Several points have been optimized: time to reach the thermodynamic equilibrium in the gas phase, syringe filling rate, gas injection rate, and volume ratio between the gas and liquid phases. This new method was used to determine partition coefficients between the liquid and gas phases and study multicomponent mixtures for which particular perceptive interactions had previously been highlighted. The partition coefficients of 9 esters and 5 higher alcohols were determined in dilute alcohol solution (12% v/v) and dearomatized red wine. These partition coefficients revealed modifications in ester headspace release in the presence of higher alcohols for the first time in this type of matrix. The correlation of these results with sensory data highlighted the role of physicochemical, presensory effects on sensory modifications for the first time, suggesting that this type of interaction may partly modulate qualitative and quantitative fruity perception.