Miniaturized analytical method to evaluate the profile of biogenic volatile organic compounds from Spanish tree species by gas chromatography coupled to mass spectrometry and chemometric tools

Abstract

A novel miniaturized analytical method has been optimized to study the biogenic volatile organic compounds (BVOCs) profile from tree leaves using headspace solid-phase microextraction gas chromatography-quadrupole time-of-flight spectrometry (HS-SPME-GC-QTOF-MS). Several parameters were tested, and a 50/30 µm DVB/CAR/PDMS SPME fiber, 0.20 g of sample, extraction and desorption times of 45 and 3 mins, respectively, were selected as the optimal conditions. Subsequently, 42 samples from Ávila (Spain) were evaluated including conifers (Pinus sylvestris and Juniperus oxycedrus) and broadleaf species (Quercus ilex and Quercus pyrenaica). More than 100 different BVOCs were tentatively identified with a matching degree >85 % in the NIST library. Total compounds were categorized into 12 main groups, where sesquiterpenoids, hydrocarbons, and alcohols were the dominant family groups. Moreover, a variety of chemometric tools were applied to enable data differentiation and potential classification of samples. Principal component analysis revealed that the BVOCs produced by different tree species exhibit distinct profiles, forming three well-defined clusters, while hierarchical cluster analysis indicated that the composition is influenced by the season, and sampling height. Finally, the method was classified as environmentally friendly according to the green analytical metrics and evaluated as practical by the blue applicability grade index.