Optimization of Head Space Sorptive Extraction to Determine Volatile Compounds from Oak Wood in Fortified Wines

Head space sorptive extraction (HSSE) has been evaluated for the analysis of volatile compounds from oak wood in wines. The extraction conditions have been optimized using a two-level factorial design. After optimization, the final extraction conditions were: PDMS stir bars (20 mm length x 0.5 mm film thickness), sample volume of 5 mL, extraction time 120 min, stirring speed 2000 rpm, and NaCl until saturation. The HSSE optimized method was further validated and showed high linearity (r (2) > 0.9960), adequate detection and quantification limits and linear ranges for the analysis of these compounds in aged wines. Moreover, it provided good values of analytical parameters such as precision and recovery (3.49-11.22 % for intra-assay precision, 4.35-8.77 % for inter-assay precision, and 70.6-124 % for recovery). The method was finally applied to different types of fortified wines (Mistelle, Fino and Oloroso wine) from Condado de Huelva Denomination of Origin submitted to different periods of aging in oak wood.