## 4 Conclusions  
In this study, a model mixture embodying a theoretical distilled spirit was prepared. It highlighted the diversity and the wide range of concentrations of flavor compounds found in liquors. When applied to the model liquor, the HS-SPME extraction method was preferred to the LLE, SPE and SBSE/HSSE methods. A study showed that the extraction was optimal with a DVB/CAR/PDMS fiber, during 60 min, at 35 \({}^{\circ}\)C and with the addition of NaCl. As shown in previous reports, a decrease of the ethanol content to 10% \(\
u/\
u\) was necessary to improve the method's efficiency. The optimized HS-SPME method was then successfully applied to gin, whiskey and rum commercial samples and led to the identification of 188 flavor compounds. While terpenids were the most abundant compounds in the gin sample, esters were the most represented chemical family in whiskey and rum. The method enabled to differentiate the compositions of the three spirits, as 121, 33 and 18 compounds were found to be specific to gin, whiskey, and rum, respectively. Finally, all four extraction techniques studied in this work showed limitations. Notably, even though the HS-SPME method developed here with a DVB/CAR/PDMS fiber provides substantial information about the flavor compounds in distilled spirits at a price appropriate for micro-distilleries, it has some disadvantages. It is not quantitative, and the extraction time is not negligible. Moreover, it appeared to be less efficient for the extraction of more polar compounds such as phenols and furans, possibly resulting in a loss of information on the flavor profile. However, when a standard chromatographic system like a single quadrupole GC-MS or GC/FID is used, this extraction step is necessary. Overall, the HS-SPME method developed here appears to be well-suited for the analysis of several distilled spirits and could be used by micro-distilleries eager to control their production, either by carrying out themselves the analysis on an affordable GC-MS equipment or by subcontracting analysis to a laboratory that will be able to use the method. Evaluation of the HS-SPME extraction method to identify compounds present in other types of distilled spirits such as vodka, tequila or brandy will be undertaken soon. In addition, this method will be used to analyze different brands of the same distilled spirit to highlight chemical specificities of a given product. In parallel, the results reported here using the HS-SPME method and direct injection without any preliminary concentration into a more sensitive chromatographic system, such as GCxGC-TOF-MS, will be compared. \begin{table}
\begin{tabular}{l l l l l l l} \hline \hline
**Chemical Class** & **Compound** & **exp. RI** & **th. RI a** & **Gin b** & **Rum b** & **Whiskey b** \\ \hline other & allyl isothiocyanate & 877 & 885 & - & tr & - \\ \hline  & unknown 1 & 750 & - & - & + & - \\  & unknown 2 & 956 & - & - & + & - \\  & unknown 6 & 1182 & - & + & - & - \\  & unknown 7 & 1200 & - & - & + & - \\  & unknown 9 & 1323 & - & - & + & - \\ unknown & unknown 12 & 1553 & - & + & - & - \\  & unknown 13 & 1554 & - & + & - & - \\  & unknown 15 & 1568 & - & - & - & + \\  & unknown 21 & 1604 & - & - & + & - \\  & unknown 22 & 1614 & - & + & - & - \\  & unknown 25 & 1687 & - & - & + & - \\ \hline \hline \end{tabular}  
* Mean RI were available from the NIST 2020 library. b Relative peak areas (TIC) were indicated as follows: “++++”: 60% \(>x\geq\) 40%; “++++”: 40% \(>x\geq\) 20%; “++”: 20% \(>x\geq\) 1%; “++”: 1% \(>x\geq\) 0.1%; “+”: 0.1% \(>x\geq\) 0.1%; “+”: 0.1% \(>x\geq\) 0.01%; “+”: 0.1% \(>x\geq\) 0.01%; “+”: x \(<\) 0.01%; “-”: not detected. c stereochemistry unknown.  
\end{table} 
Table 4: _Cont._  
**Supplementary Materials:** The following supporting information can be downloaded at [[https://www.mdpi.com/article/10.3390/foods11213358/s1](https://www.mdpi.com/article/10.3390/foods11213358/s1)]([https://www.mdpi.com/article/10.3390/foods11213358/s1](https://www.mdpi.com/article/10.3390/foods11213358/s1)).