Development, validation and application of a specific method for the quantitative determination of wine esters by headspace-solid-phase microextraction-gas chromatography–mass spectrometry
ABSTRACT A method for specifically quantifying 32 apolar esters in wine is reported that employs head space solid phase microextraction (HS-SPME) followed by gas chromatography–mass spectrometry (GC–MS). A dozen esters were studied for the first time in wines, among them methyl trans-geranate, never reported in red wines until now. The target esters were apolar but bore a broad range of functional groups and have concentrations ranging from mg/l to ng/l levels; polar esters being effectively extracted by dichloromethane. Extraction and desorption conditions were optimised to obtain the best compromise for the simultaneous analysis of all 32 studied esters. To provide specificity for the method, deuterated ethyl esters were used as internal standards. These were ethyl-d5 butyrate, hexanoate, octanoate and cinnamate, synthesised from the appropriate acyl chloride and ethanol-d6. The esters were quantified in the wines with satisfactory repeatability (1.8% < RSD < 11.2%), reproducibility (1.5% < RSD < 15%), sensitivity (0.4 ng/l < LOQ < 4 μg/l), accuracy and specificity. The validation was carried out with several wine types as matrices (red, dry and sweet white). The optimised method was applied to 19 French wines and the results confirmed some well established oenological principles and opened prospects for further study on wine esters that had not been previously measured.
Article: Free and bound aroma compounds characterization by GC-MS of Negroamaro wine as affected by soil management.[show abstract] [hide abstract]
ABSTRACT: Negroamaro is an autochthonous wine grape variety of Southern Italy, which is becoming very important for the Italian wine market. The wine aroma is primary affected by the chemical composition of grapes, which can be influenced also by agronomic practices such as soil management. In this study, the free and bound aroma characterization was performed by gas chromatography-mass spectrometry analyses, and the influence of two soil managements (cover cropping and soil tillage) was evaluated. A total of 40 volatile compounds were observed in the wine samples. Alcohols (55.7 mg/L), fatty acids (7.0 mg/L) and esters (6.6 mg/L) were found as the main classes in Negroamaro wine. The results showed that the aroma composition of Negroamaro wine was positively affected by soil tillage probably because of the higher water stress (ψ(s) ) recorded in the vines from this treatment. Indeed, among the free volatile compounds, higher contents of esters, carboxylic acids, alcohols, phenolics and acetamides together with lower contents of sulfurs compounds were found in soil tillage wine. Conversely, no difference was observed in glycoside volatile compounds. Copyright © 2012 John Wiley & Sons, Ltd.Biological Mass Spectrometry 09/2012; 47(9):1104-12. · 3.41 Impact Factor