Application of Multiple Headspace Solid Phase Microextraction(MHS-SPME) technique to the quantitative analysis of fragrance andflavour compounds

Solid phase microextraction is a simple and rapid extraction technique based on the partition of an analyte between its matrix and the coating of a fused-silica fiber, introduced for the first time by Arthur and Pawliszyn [1]. This technique is very powerful for the determination of volatiles and semi-volatiles in a wide variety of samples. Since it is a non-exhaustive technique, only a small portion of the analyte is removed from the sample. However, for standard solutions, there is a linear correlation between the amount extracted by the fiber and the real amount present in the sample matrix, thus calibration curves can be built up for quantitative purpose. Totally different is the case of absolute quantitation of analytes in complex-matrix samples because the distribution constants depend on the composition and the polarity of the sample. To avoid the matrix effect, multiple extractions can be performed and the peak area of few successive analyses used to calculate the total amount of the analytes in the sample [2]. This technique is called Multiple Headspace Extraction (MHS) and its theory has been described by Ezquerro et al. [3] In this work, multiple headspace solid-phase microextraction, coupled with GC-MS and GC-FID, have been applied to the qualitative and quantitative analyses of standard compounds typical of fragrances and flavours. Vaseline oil has been used as matrix and the fiber chosen was 65µm polydimethylsiloxane/divinylbenzene (PDMS/DVB). Different amounts of samples and dilutions were tested in order to optimize the MHS-SPME extraction and the calibration curves for the quantification of each analyte were built-up.