Bozalongo Ruth, Carrillo José David, Torroba Miguel Angel Fernández, Tena María Teresa
Department of Chemistry, University of La Rioja, C/Madre de Dios, 51, E-26006 Logroño (La Rioja), Spain.
J Chromatogr A. 2007 Nov 30;1173(1-2):10-7. doi: 10.1016/j.chroma.2007.09.079. Epub 2007 Oct 10.
This paper describes the optimisation of headspace solid-phase microextraction (HS-SPME) conditions for the analysis of volatile compounds in oak chips used to accelerate wine aging as an alternative to traditional aging in oak barrels. The direct extraction of ground wood samples and the extraction of sample aqueous slurries using a divinylbenzene-carboxen-polydimethylsiloxane (DVB-CAR-PDMS) fibre were studied and compared. Optimal conditions for direct extraction were 110 degrees C and 60 min, whereas for aqueous slurries they were obtained by adding 2mL of a 7.1 molL(-1) sodium chloride solution, at 70 degrees C and for 60 min. The two optimised HS-SPME approaches were compared in terms of repeatability and extraction efficiency; water addition to the sample prior to HS-SPME was selected because it yielded better repeatability (6.6% versus 8.5% relative standard deviation) and efficiency (around 1.4-4.8 times higher analyte amount extracted for most of the compounds). Finally, the method was applied in the analysis of oak chip samples from American and French oak with different degrees of toasting. Principal component analysis (PCA) of the results showed that the first principal component was correlated with the toasting degree whereas the second, which was strongly influenced by whisky lactones and eugenol, allowed us to differentiate between American and French oak chips.
本文描述了顶空固相微萃取（HS-SPME）条件的优化，用于分析用于加速葡萄酒陈酿的橡木片中的挥发性化合物，作为橡木桶传统陈酿的替代方法。研究并比较了使用二乙烯基苯-碳分子筛-聚二甲基硅氧烷（DVB-CAR-PDMS）纤维对磨碎的木材样品进行直接萃取以及对样品水浆进行萃取的情况。直接萃取的最佳条件为110℃和60分钟，而对于水浆萃取，通过加入2mL 7.1 molL（-1）氯化钠溶液，在70℃下萃取60分钟获得最佳条件。比较了两种优化的HS-SPME方法的重复性和萃取效率；选择在HS-SPME之前向样品中加水，是因为它具有更好的重复性（相对标准偏差为6.6%对8.5%）和效率（对于大多数化合物，萃取的分析物量高出约1.4 - 4.8倍）。最后，该方法应用于分析来自美国和法国不同烘烤程度的橡木片样品。结果的主成分分析（PCA）表明，第一主成分与烘烤程度相关，而第二主成分受威士忌内酯和丁香酚的强烈影响，使我们能够区分美国和法国橡木片。
