Comprehensive two-dimensional gas chromatography (GC × GC) is amongst the most powerful separation technologies currently existing. Since its advent in early 1990, it has become an established method which is readily available. However, one of its most challenging aspects, especially in hyphenation with mass spectrometry is the high amount of chemical information it provides for each measurement. The GC × GC community agrees that there, the highest demand for action is found. In response, the number of software packages allowing for in-depth data processing of GC × GC data has risen over the last couple of years. These packages provide sophisticated tools and algorithms allowing for more streamlined data evaluation. However, these tools/algorithms and their respective specific functionalities differ drastically within the available software packages and might result in various levels of findings if not appropriately implemented by the end users. This study focuses on two main objectives. First, to propose a data analysis framework and second to propose an open-source dataset for benchmarking software options and their specificities. Thus, allowing for an unanimous and comprehensive evaluation of GC × GC software. Thereby, the benchmark data includes a set of standard compound measurements and a set of chocolate aroma profiles. On this foundation, eight readily available GC × GC software packages were anonymously investigated for fundamental and advanced functionalities such as retention and detection device derived parameters, revealing differences in the determination of e.g. retention times and mass spectra.

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Allergic diseases are an increasing global burden. Epidemiological and in vivo studies showed that farming environments could protect from allergic asthma. Studies explaining this protective effect mainly focused on the influence of chemical compounds in the molecular size range of proteins and endotoxins. Our study aimed at deciphering the possible role of small-sized semi-volatile organic compounds (SVOCs) of farming aerosols in immunomodulation processes. Bronchial epithelial BEAS-2B cells were exposed to aerosol extracts of particulate matter (PM2.5) from farming environments. These cell exposures revealed a decisive effect of the smaller sized fraction (< 3 kDa) compared to extracts including the larger sized fraction. We demonstrated that smaller compounds can induce regulations of inflammatory and allergy-related genes including interleukin-8, xanthine dehydrogenase and toll-like receptor 2 (TLR2). Additionally, we performed a comprehensive chemical investigation of two typical farming aerosols (cow vs. sheep) by applying comprehensive gas chromatography coupled to time-of-flight mass spectrometry. We were able to identify several SVOCs characteristic for the protective cow sheds environment including four key components. Cell exposure with the two farming extracts showed a distinct regulation of the E3 ubiquitin ligase PELI2 gene and TLR2 by cow shed extracts. Finally, the regulation of TLR2 corresponded to the regulation that was observed after exposing cells to an artificial mixture of the four key components identified in the cow sheds. In summary, we were able to demonstrate the importance of smaller particle-bound SVOCs found in farming environments concerning their possible contribution to a protective farm effect.