Accurate and robust method for plant volatilome analysis by GC-MS

The volatilome encompasses all volatile organic compounds (VOCs) emitted by an organism. Plants typically produce VOCs belonging to distinct chemical classes, including aldehydes, ketones, esters, and terpenes, which are involved in various biological and ecological functions such as intra- and interspecific communication, defense against herbivores, and pollination. Furthermore, the VOC profile contributes to the organoleptic properties of plants, influencing their commercial value in the food and agricultural markets1. VOCs composition can also vary in response to different stimuli to which the plant is subjected, leading to the formation of new evolved molecules or very subtle concentration variations, resulting in a great variability in the collected samples2. Consequently, the sample collection method and analysis must be robust and reliable, to minimize the uncertainty that affects the results. Gas-chromatography tandem mass spectrometry (GC-MS) is currently regarded as the gold standard for identifying and quantifying such molecules in this type of samples, due to their high sensitivity and selectivity3; for this reason, this work proposes a quantitative GC-MS method, optimized and validated following the AOAC Guidelines4 for fifteen VOCs typically present in Solanum lycopersicum (tomato plant). Different figures of merit have been evaluated, including linearity and alternative fitting models by means of ANOVA and F-test, limits of detection and quantification, inter- and intra-day precision. The validated method has been then applied to real tomato plant volatilome samples collected with a tailored setup with an airtight entrainment system, forced to pass through an adsorption cartridge. The analytes were then eluted through a solvent desorption before GC-MS analysis; this step has been also evaluated in terms of recovery, in order to assess the trustworthiness of the data obtained. The method developed in this study serves as a highly reliable analytical tool for characterizing plant volatilome. By integrating optimized protocols for gas chromatography-mass spectrometry (GC-MS) with meticulous validation processes, this approach enhances our ability to investigate plant secondary metabolism and its ecological significance. These insights lay the foundation for enhancing the quality and resilience of agricultural products while deepening our understanding of plant-environment interactions