## 3 Results and Discussion
### Comparison with Other Analytical Methodologies  
Considering that there are no previous works on volatile sulphur compounds in wine distillates using SBSE-GC-MS, the developed methodology was compared with other analytical techniques applied to different alcoholic beverages. In terms of the DL values, the present methodology exhibited improved values with respect to methods such as the determination of DES, DMDS, DPS, DMTS, and DPDS in whisky by HS-SPME-AED; DES and DMDS in wine by HS-GC-pFPD; and DES, DEDS, and DMDS in wine by HS-GC-SCD with cryofocusing (Table 5). However, some authors [11; 13; 14] obtained, in some cases, lower DL values employing HS-SPME. In these studies, divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) arrow fibers and carboxen-polydimethylsiloxane (CAR/PDMS) and (DVB/CAR/PDMS) fibers, which have slightly higher polarity and higher retention capacity than PDMS, were used. The DL and QL values obtained in the present work were, in general, low enough to quantify the eight VSCs studied (Appendix A, Table A2). If it were necessary to improve the sensitivity of the present methodology, it could be achieved using Tandem Mass Spectrometry, also known as MS/MS or MS2. On the other hand, the current analytical methodology presented recovery, repeatability, and reproducibility values similar to those based on SPME (Table 5), using extraction times and temperatures similar to this one, but with the advantage that, in the case of SBSE, several extractions can be easily performed in parallel. Therefore, the SBSE-GC-MS method developed can be truly used to identify and quantify eight volatile sulphur compounds in grape distillate samples at very low concentrations. \begin{table}
\begin{tabular}{l c c c c c c c} \hline \hline \multirow{2}{*}{**Compound**} & \multirow{2}{*}{\begin{tabular}{c} **Concentration Range** \\ **(\#/L)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Calibration** \\ **Curve (\(\mathbf{r^{2}}\))** \\ \end{tabular} } & \multirow{2}{*}{**DL (\(\mu\)g/L)**} & \multirow{2}{*}{**QL (\(\mu\)g/L)**} & \multicolumn{2}{c}{**Repeatibility (\%)**} & \multirow{2}{*}{**Recovery**} \\ \cline{3-4}  & & & & & **Inter-Twister** & & **Inter-Day** & **(\%)** \\ \hline EMS & - & - & - & - & 15.4 & 14.5 & - \\ DES & 1.00–25.0 & \begin{tabular}{c} 0.0009x + 0.0058 \\ (0.9961) \\ \end{tabular} & 0.9293 & 3.0977 & 8.1 & 12.1 & 116.4 \\ P & - & - & - & - & 36.5 & 38.2 & - \\ DMDS & 0.10–30.0 & \begin{tabular}{c} 0.0027x + 0.0018 \\ (0.9958) \\ \end{tabular} & 0.1830 & 0.6101 & 6.3 & 7.2 & 110.1 \\ DPS & 0.10–1.00 & \begin{tabular}{c} 0.0057x + 0.0011 \\ (0.9963) \\ \end{tabular} & 0.0396 & 0.1321 & 14.4 & 22.1 & 116.8 \\ DEDS & 0.10–1.00 & \begin{tabular}{c} 0.0133x \(-\) 0.0007 \\ (0.9909) \\ \end{tabular} & 0.0676 & 0.2254 & 5.9 & 13.8 & 119.4 \\ DBS & 0.025–5.00 & \begin{tabular}{c} 0.0055x + 0.0073 \\ (0.9972) \\ \end{tabular} & 0.1678 & 0.5595 & 21.8 & 27.5 & 109.3 \\ DITS & 0.25–10.0 & \begin{tabular}{c} 0.0089x + 0.0002 \\ (0.9980) \\ \end{tabular} & 0.2376 & 0.7921 & 7.5 & 10.6 & 113.6 \\ DPDS & 0.10–1.00 & \
\begin{tabular}{c} 0.0167x \(-\) 0.0002 \\ (0.9966) \\ \end{tabular} & 0.0382 & 0.1274 & 9.6 & 26.5 & 108.8 \\ TC & 0.25–15.0 &
\begin{tabular}{c} 0.0006x + 0.0004 \\ (0.9970) \\ \end{tabular} & 0.4893 & 1.6310 & 18.7 & 27.4 & 84.8 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Validation study. Regarding the green character of the SBSE-GC-MS method, the Analytical Greenness Calculator (AGREE) was used [29]. In this, the greenness and efficiency of each analytical method is evaluated and an overall global score from 0 to 1 is established (0, low; 1, high). In the case of the present methodology, this global score was 0.71, equal to that reported by [PERSON] et al. [12] using HS-SPME-GC- pFPD for the determination of DES and DMDS in wines (Figure 2). Both methodologies are characterized by the use of low sample volumes, no hazardous materials, no solvents, and low energy consumption. The lowest global scores were obtained by [PERSON] et al. [1], [PERSON] et al.