Optimization of headspace sorptive extraction for the analysis of volatiles in pressed ewes' milk cheese

An analytical method was developed for simultaneous determination of 50 volatiles in pressed ewe cheese using headspace sorptive extraction coupled to a thermal desorption and gas chromatography mass spectrometry. Method optimization was carried out in terms of chromatographic columns and conditions, stir bar size and holder, vial volume, salt content, sample weight, extraction temperature and time. The proposed method was validated showing good results in linearity (>0.98), precision (9-34%), recovery (58-120%), limit of detection (6-38 ng kg(-1)) and limit of quantitation (75-150 ng kg(-1)). The present method was also applied for the analysis of volatiles in ewes' milk cheese samples. (C) 2011 Elsevier Ltd. All rights reserved.