Pubblicazioni

The analysis of samples with strong matrices often presents challenges during sample preparation and analysis, particularly in the determination of volatile compounds using gas chromatography-mass spectrometry (GC-MS). Usually, one triesanattempt is made to separate the matrix from the sample, which often are often elaborate procedures. In many cases, headspace analysis alone is not sensitive or sufficient. Therefore, microextraction methods such as solid-phase microextraction (SPME) [1] and in-tube extraction (ITEX) [2] have gained attention in the last decades. These techniques show additional advantages such as automatability, sustainability, easy application and no solvent consumption. In complex matrices, the concentrations of different compounds can vary widely, which is a problem when using SPME because the phase volume is small and saturates quickly saturated. ITEX techniques have a much larger phase volume and achieve higher enrichment factors when the sample headspace is sucked through the sorbent material several times. However, it has been found that the performance of headspace techniques is improved under reduced pressure, as demonstrated by vacuum SPME techniques [3]. We present here a technique in which classical ITEX was applied under vacuum, called Dynamic Headspace Vacuum In-Tube Extraction (V-ITEX, based on the DHS-VTT technique [4]), which was compared with classical ITEX and SPME and applied to several different matrices. In addition, a simple modification of the autosampler was carried out in order to apply V-ITEX automatically. The extraction of volatiles by V-ITEX is fast, shows low artefact formation and a higher evaporation rate of the compounds. Compared to classical techniques, V-ITEX is more time efficient and more sensitive. The higher extraction efficiency allows the analysis of smaller sample volumes, the use of split systems with two or more detectors or integration into olfactometric analyses. In conclusion, the V-ITEX technique is very promising for the field of volatile analysis.