Headspace solid-phase microextraction (HE-SPME) is a solvent-free sample preparation technique that can be used to extract and concentrate a wide range of volatile compounds from different matrices in a single step. It has been used routinely in combination with GC/MS and GC/FID to characterise food volatile compounds, although there have been few reports of applications on its absolute quantification. Two important requirements for quantitative analysis using HE-SPME are good reproducibility for replicated samples and a linear response over the range of concentration at which the analyte is expected to occur in the sample. SPME quantitative analysis is feasible in a non-equilibrium situation as long as the agitation conditions and adsorption time are held constant, and biases due to competition or linear range excesses are controlled. The ability to use HE-SPME quantitatively before reaching equilibrium permits much shorter sampling times. This review describes HE-SPME methods in combination with GC/MS or GC/FID for extraction, identification and quantification of volatile compounds in food matrices. Standard additions method and isotope dilution assays are described as the most reliable methods for quantification.
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