| Title: | Multiple automated headspace in-tube extraction for the accurate analysis of relevant wine aroma compounds and for the estimation of their relative liquid-gas transfer rates |
| Author(s): | Zapata J; Lopez R; Herrero P; Ferreira V; |
| Address: | "Laboratory for Flavor Analysis and Enology, Institute of Engineering of Aragon, I3A, Department of Analytical Chemistry, Faculty of Sciences, University of Zaragoza, 50009 Zaragoza, Spain" |
| DOI: | 10.1016/j.chroma.2012.10.015 |
| ISSN/ISBN: | 1873-3778 (Electronic) 0021-9673 (Linking) |
| Abstract: | "An automated headspace in-tube extraction (ITEX) method combined with multiple headspace extraction (MHE) has been developed to provide simultaneously information about the accurate wine content in 20 relevant aroma compounds and about their relative transfer rates to the headspace and hence about the relative strength of their interactions with the matrix. In the method, 5 muL (for alcohols, acetates and carbonyl alcohols) or 200 muL (for ethyl esters) of wine sample were introduced in a 2 mL vial, heated at 35 degrees C and extracted with 32 (for alcohols, acetates and carbonyl alcohols) or 16 (for ethyl esters) 0.5 mL pumping strokes in four consecutive extraction and analysis cycles. The application of the classical theory of Multiple Extractions makes it possible to obtain a highly reliable estimate of the total amount of volatile compound present in the sample and a second parameter, beta, which is simply the proportion of volatile not transferred to the trap in one extraction cycle, but that seems to be a reliable indicator of the actual volatility of the compound in that particular wine. A study with 20 wines of different types and 1 synthetic sample has revealed the existence of significant differences in the relative volatility of 15 out of 20 odorants. Differences are particularly intense for acetaldehyde and other carbonyls, but are also notable for alcohols and long chain fatty acid ethyl esters. It is expected that these differences, linked likely to sulphur dioxide and some unknown specific compositional aspects of the wine matrix, can be responsible for relevant sensory changes, and may even be the cause explaining why the same aroma composition can produce different aroma perceptions in two different wines" |
| Keywords: | Chemical Fractionation/*instrumentation/*methods Gas Chromatography-Mass Spectrometry/*methods Gases/analysis Odorants/*analysis Reproducibility of Results Volatile Organic Compounds/*analysis Wine/*analysis; |
| Notes: | "MedlineZapata, Julian Lopez, Ricardo Herrero, Paula Ferreira, Vicente eng Research Support, Non-U.S. Gov't Netherlands 2012/10/30 J Chromatogr A. 2012 Nov 30; 1266:1-9. doi: 10.1016/j.chroma.2012.10.015. Epub 2012 Oct 16" |
