Dynamic and static collection followed by a GC–MS analysis of volatiles from Chagasic bugs’ feces: a case of short chain aldehydes

In the study on volatile semiochemicals, we employed two headspace sampling methods: static and dynamic. Static headspace analysis utilized Solid Phase Microextraction (SPME), while dynamic headspace sampling involved techniques such as push–pull and closed loop stripping. Both methods are crucial for accurately detecting and characterizing the volatile profile of bloodsucking arthropods in situ or in vitro. This study examines differences in the chemical composition of volatiles extracted from the feces of two Chagasic bug species, Triatoma phyllosoma and Rhodnius prolixus, employing SPME and dynamic aeration techniques. Additionally, a standard synthetic blend of compounds (heptanal, octanal, nonanal, and decanal) mimicking a natural combination was utilized, with the evaporation of the blend monitored through gas chromatography-mass spectrometry (GC–MS) analysis. Volatiles were captured using seven distinct SPME fiber types and adsorbents: Tenax®, Super Q®, and activated charcoal. Comparative analysis was conducted between the amount and ratios of evaporated and those captured using dynamic and static headspace sampling methods. The advantages and disadvantages of each technique were thoroughly examined. Results indicate that activated charcoal, Tenax®, and the polydimethylsiloxane (PDMS)/divinylbenzene (DVB) fiber demonstrate superior accuracy in capturing short-chain aldehydes. Furthermore, the significance of employing multiple headspace sampling techniques within a chemical ecology framework is discussed.