## 2 Results and Discussion
### Validation and Comparison of Both Methodologies  
After optimizing both methodologies (HS-SPME-fiber: PDMS/DVB, HS temperature: 30 \({}^{\circ}\)C, equilibrium time: 30 min and desorption time: 5 min; HS-BA\(\mu\)E- sorbent: AC(R), HS temperature: 30 \({}^{\circ}\)C, equilibrium time: 3 h and desorption solvent: \(n\)-C\({}_{6}\)), validation assays were performed, including analytical thresholds, linear dynamic ranges, precision and accuracy. Table 1 summarizes the analytical data obtained from the parameters evaluated during the validation assays for both methodologies, under optimized experimental conditions. Analytical thresholds were evaluated through the determination of the LODs and LOOs, in which the values achieved were in the ranges of 25.0-50.0 ng L\({}^{-1}\) and 75.0-175.0 ng L\({}^{-1}\) for HS-SPME(PDMS/DVB), whereas 5.0 \(\mu\)g L\({}^{-1}\) and 16.6 \(\mu\)g L\({}^{-1}\) were obtained for HS-BA\(\mu\)E(R), respectively (Table 1). Nevertheless, this difference is not surprising according to the analytical configuration adopted, since HS-SPME resorts to an approach in which the matrix sampled in the fiber is fully analyzed ('one-shot analysis') by thermal desorption (TD), reflected by the lowest LODs achieved, whereas the HS-BA\(\mu\)E relies on LD, where only a portion (1 \(\mu\)L) is injected into the GC-MS system. The linear dynamic ranges were found through the analysis of the standard mix solutions of the five monoterepnoids ranging from 0.5 to 17.5 \(\mu\)g L\({}^{-1}\) (HS-SPME(PDMS/DVB)) and between 20.0 and 100.0 mg L\({}^{-1}\) (HS-BA\(\mu\)E(R)), where remarkable linearity was found (\(r^{2}\geq 0.9959\)). Nevertheless, the \(r^{2}\) is not enough to verify the linearity of the regressions, since the evaluation of the heteroscedasticity data remains unassessed. In this sense, the homoscedasticity data were evaluated through the lack-of-fit test and residues dispersion [12]. For the conventional linear regressions plotted, the lack-of-fit test showed a good fit (at a confidence level of 95%) of the calibration curves (i.e., F\({}_{\rm exp}<\) F\({}_{\rm lab}\)), suggesting a homoscedastic distribution of the experimental data. Moreover, through the study of the residue plots, an unsystematic distribution of the relative residues was verified, which confirms the homoscedasticity of the experimental data, as well as the suitability of the linear regressions plotted for the analyses of the five monoterepnoids. Furthermore, the lower limit of quantification (LLOQ) of the five BVOCs was determined for both analytical \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{3}{*}{**Monoterrepenoids**} & \multicolumn{6}{c}{**HS-SPME(PDMS/DVB)**} & \multicolumn{6}{c}{**HS-BA\(\mu\)E(R)**} \\ \cline{2-11}  & \multirow{2}{*}{\begin{tabular}{c} LOD \\ (ng L\({}^{-1}\)) \\ \end{tabular} } & \multirow{2}{*}{\
\begin{tabular}{c} LOQ \\ (ng L\({}^{-1}\)) \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} Linear \\ (ng L\({}^{-1}\)) \\ \end{tabular} } & \multirow{2}{*}{\(a\)} & \multirow{2}{*}{\(b\)} & \multirow{2}{*}{\(r^{2}\)} & \multirow{2}{*}{\(LOD\)} & \multirow{2}{*}{\(LOQ\)} & \multirow{2}{*}{\(Lugar\)} & \multirow{2}{*}{\(a\)} & \multirow{2}{*}{\(b\)} & \multirow{2}{*}{\(r^{2}\)} \\  & & & & & & & & & & & \\ \hline \(\alpha\)-Pinene & 25.0 & 75.0 & & 26.193 & \(-\)0.029 & 0.9987 & & & 4.731 & \(-\)0.276 & 0.9976 \\ \(\beta\)-Pinene & 50.0 & 175.0 & & 32.305 & \(-\)0.047 & 0.9984 & & & 4.734 & \(-\)0.296 & 0.9991 \\ Myrence & 50.0 & 175.0 & & 0.5-17.5 & 51.874 & \(-\)0.480 & 0.9985 & & 16.6 & 20.0– & 4.508 & \(-\)0.256 & 0.9959 \\ Limonene & 25.0 & 75.0 & & 75.885 & \(-\)0.324 & 0.9989 & & & 100.0 & 5.630 & \(-\)0.201 & 0.9965 \\
1,8-Cineole & 25.0 & 175.0 & & 54.062 & 0.581 & 0.9966 & & & 7.184 & \(-\)0.362 & 0.9976 \\ \hline \hline \end{tabular}
\end{table}