## 4 Conclusions  
A novel analytical approach (HS-BA\(\mu\)E(CN1)/GC-MS) is proposed for monitoring BVOCs, particularly terpenoids, from six different Portuguese shrub species (_Erica scoparia_ L., _Cistus ladanifer_ L., _Cistus nonspeliensis_ L., _Lavandula stoechas_ L., _Thymus villosus_ L., and _Thymus camphoratus_). The methodology underwent optimization and validation and demonstrated robustness, sensitivity, selectivity, and excellent performance. Comparison with the reference methodology, HS-SPME(PDMS/DVB), showed comparable analytical responses and excellent reproducibility.  
Among the six shrub species investigated, _Thymus camphoratus_ exhibited the highest emissions of BVOCs from its leaves, notably 1,8-cineole (4136.9 \(\pm\) 6.3 \(\mu\)g/g), \(\alpha\)-pinene (763.9 \(\pm\) 0.5 \(\mu\)g/g), and \(\beta\)-pinene (259.3 \(\pm\) 0.5 \(\mu\)g/g). It was also the only species found to release cryophyllene oxide (411.4 \(\pm\) 0.3 \(\mu\)g/g). These observed levels suggest that the shrub species could potentially contribute to fuel sources in the event of forest fires under extreme conditions.  
In summary, the proposed methodology emerged as a favorable analytical alternative for BVOC screening in plants. It not only demonstrated outstanding performance but also exhibited user- and eco-friendliness, cost-effectiveness, and ease of implementation.  
Conceptualization, J.S.R.F.C. and J.M.F.N.; methodology, J.S.R.F.C.; validation, J.S.R.F.C.; formal analysis, J.S.R.F.C.; investigation, J.S.R.F.C. and J.M.F.N.; resources, J.M.F.N.; data curation, J.M.F.N.; writing--original draft preparation, J.S.R.F.C.; writing--review and editing, J.M.F.N.; visualization, J.M.F.N.; supervision, J.M.F.N.; project administration, J.M.F.N.; funding acquisition, J.M.F.N. All authors have read and agreed to the published version of the manuscript.  
This research was funded by Extreme Project; PIDDAC: PCIF/GFC/0078/2018; UIDB/ 00100/2020; UIDP/00100/2020; LA/P/0056/2020. The authors thank Centro de Quimica Estrutural as a Research Unit funded by Fundacao para a Ciencia e a Tecnologia (FCT) through projects UIDB/00100/2020 ([[https://doi.org/10.54499/UIDP/00100/2020](https://doi.org/10.54499/UIDP/00100/2020)]([https://doi.org/10.54499/UIDP/00100/2020](https://doi.org/10.54499/UIDP/00100/2020))) and UIDP/00100/2020 ([[https://doi.org/10.54499/UIDB/00100/2020](https://doi.org/10.54499/UIDB/00100/2020)]([https://doi.org/10.54499/UIDB/00100/2020](https://doi.org/10.54499/UIDB/00100/2020))), as well as the Institute of Molecular Sciences, an Associate Laboratory funded by FCT through project LA/P/0056/2020 ([[https://doi.org/10.54499/LA/P/0056](https://doi.org/10.54499/LA/P/0056)]([https://doi.org/10.54499/LA/P/0056](https://doi.org/10.54499/LA/P/0056)) /2020). They also acknowledge the support received from national funds (Extreme Project; PIDDAC: PCIF/GFC/0078/2018) and the MSc grant awarded to [PERSON]. [PERSON].  
The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.  
The authors express their gratitude to [PERSON] and [PERSON] from Instituto Superior de Agronomia and [PERSON] from Faculdade de Ciencias da Universidade de Lisboa (FCUL) for their efforts in sampling shrub leaves, as well as to [PERSON] from FCUL for providing standards.  
The authors declare no conflict of interest.