Static Headspace Extraction with Compounds Trapping for the Analysis of Volatile Lipid Oxidation Products

Abstract

Static headspace is an easy to perform, convenient, and usually automated method for extraction of volatiles from various food matrices. Among other applications, it is used also for monitoring of volatile lipid oxidation products. However, the biggest disadvantage of this method is its low sensitivity especially when compared to such techniques as solid-phase microextraction or dynamic headspace. This paper focuses on the comparison of static headspace analysis of volatile lipid oxidation products with a modification of this technique, where volatiles extracted multiple times from oil matrix in a headspace vial are trapped on Tenax trap and subsequently desorbed into gas chromatograph. Twenty volatile compounds (mainly alkanals, 2-alkenals, ketones, and alcohols being volatile lipid oxidation products) in rapeseed oil were used for method comparison. For all compounds, a significant increase in method sensitivity and improvement of limits of detection (10 to 33 times) depending on the compound were noted; however, the repeatability was worse (for 16 out of 20 compounds) and carry-over values (also 16/20) were higher for combined headspace/trapping method.