Miniaturized GC–MS Method for BVOC Analysis of Spanish Trees

A team of scientists from the Analytical Chemistry Group (TESEA) at the University of Valladolid in Spain, has developed and validated a miniaturized, environmentally friendly method for profiling biogenic volatile organic compounds (BVOCs) from tree species using headspace solid-phase microextraction gas chromatography–quadrupole time-of-flight mass spectrometry (HS-SPME-GC–QTOF-MS). The study was published in the Journal of Chromatography Open (1).

Valladolid University © demachy - stock.adobe.com

BVOCs are compounds produced by plants and are involved in plant growth, reproduction, and defense (2). They are emitted into the atmosphere and can react with other gases to form ozone pollution (3). It is therefore essential to understand the role of BVOCs and the impact that they can have on the planet. Past studies have shown that plants can produce flammable BVOCs when exposed to heat, which could potentially trigger wildfires faster and at greater heights (4,5). In this study, the team focused on trees from Ávila, a wildfire-affected province in the Iberian Peninsula. With climate change intensifying wildfire risks, Spain and other Mediterranean countries need precise, localized data on tree emissions.

An HS-SPME-GC-QTOF-MS method was developed and optimized that enables comprehensive VOC profiling using 0.20 g of leaf material. Using a 50/30 µm DVB/CAR/PDMS fiber, the team achieved optimal extraction (45 min) and desorption (3 min) times for a broad array of BVOCs. These conditions maximized sensitivity while eliminating the need for solvents, derivatization, or energy-intensive sample prep steps such as sonication or centrifugation. The optimized protocol delivered high-resolution spectra for more than 100 compounds. This included representatives from 12 main chemical groups—particularly sesquiterpenoids, hydrocarbons, and alcohols.

The research team profiled 42 samples across four native tree species—Pinus sylvestris, Juniperus oxycedrus, Quercus ilex, and Quercus pyrenaica—over three seasons (spring, summer, and winter) and three canopy heights. Results showed distinct species- and season-specific BVOC patterns. For example, J. oxycedrus exhibited the highest proportion of sesquiterpenoids (34%), while P. sylvestris emitted elevated hydrocarbons in warmer months—a possible stress response.

Principal component analysis (PCA) and hierarchical clustering revealed strong correlations between species type, sampling height, and seasonal changes. These chemometric results not only validate the method’s analytical robustness but also highlight the potential of BVOCs as chemical markers for species identification.

The method’s environmental credentials were confirmed using AGREE, AGREEprep, ComplexGAPI, and the Blue Applicability Grade Index (BAGI), scoring 67.5—well above the 60-point threshold for practical applications.

The method’s low sample and energy demands offer a replicable, scalable approach for laboratories focused on environmental or atmospheric studies. The team concluded that this new analytical tool can be used for a variety of tree species and regions and that its environmentally friendly aspect can expand the study of BVOCs across different ecosystems (1). As wildfires continue to reshape ecosystems, the ability to track plant-emitted volatiles with precision and sustainability will only grow in importance.

References

(1) Fuente-Ballesteros, A.; Ares, A. M.; Bernal, J.; Valverde, S. 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. J. Chromatogr. Open 2025, 7, 100208. DOI: 10.1016/j.jcoa.2025.100208

(2) Peñuelas, J.; Staudt M. BVOCs and Global Change. Trends Plant Sci. 2010, 15 (3), 133–144. DOI: 10.1016/j.tplants.2009.12.005.

(3) Calfapietra, C.; Fares, S.; Manes, S.; et al. Role of Biogenic Volatile Organic Compounds (BVOC) Emitted by Urban Trees on Ozone Concentration in Cities: A Review. Environ. Pollut. 2023, 183, 71–80. DOI: 10.1016/j.envpol.2013.03.012

(4) Chatelon, F.-J.; Sauvagnargues, S.; Dusserre, G.; Balbi, J.-H. Generalized Blaze Flash, A “Flashover” Behavior for Forest Fires—Analysis from the Firefighter’s Point of View. Open J. For. 2014, 4, 547–557. DOI: 10.4236/ojf.2014.45059

(5) Chetehouna, K.; Barboni, T.; Zarguili, I.; et al. Investigation on the Emission of Volatile Organic Compounds From Heated Vegetation and their Potential to Cause an Accelerating Forest Fire. Environ. Res. Lett. 2009, 181, 1273–1288. DOI: 10.1080/00102200903181827