# HS-SPME Combined with GC-MS/O to Analyze the Flavor of Strong Aroma Baijiu _Daqu_
## 3 Results
### Quantitative Analysis of Aroma Components in Daqu by MHS-SPME
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**No.** & **Compounds** & **CAS** & **Aroma** & **Identificationa** & **RI** & & **Olfactory Intensity** \\ \cline{3-10}  & & **Number** & **Description** & & **DB-WAXb** & **HP-5c** & **DB-WAX** & **HP-5** \\ \hline
1 & Ethyl 3-methylbutanoate & 108-64-5 & fruity & MS, aroma, RI, S & 1071 & 859 & 2.2 & 2.0 \\
2 & Ethyl butyrate & 105-54-4 & fruity & MS, aroma, RI, S & 1026 & — & 1.3 & — \\
3 & Ethyl valerate & 539-82-2 & fruity & MS, aroma, RI, S & 1142 & 898 & 1.0 & 3.5 \\
4 & Limmeene & 138-86-3 & sour/sweat & MS, aroma, RI, S & 1189 & — & 2.7 & — \\
5 & Ethyl hexanoate & 123-66-0 & fruity & MS, aroma, RI, S & 1240 & 1001 & 2.5 & 3.0 \\
6 & 2,6-Dimethylpyrazole & 108-50-9 & wheat/rossted & MS, aroma, RI, S & 1347 & — & 4.0 & — \\
7 & 2,3-Dimethylpyrazole & 5910-89-4 & wheat/cocoa & MS, aroma, RI, S & 1349 & 922 & — & 3.7 \\
8 & Dimethyl trisulfide & 3658-80-8 & garlic & MS, aroma, RI, S & 1370 & 975 & 4.0 & 3.8 \\
9 & 3-Ethyl-2- & 15707-23-0 & roasted & MS, aroma, RI, S & 1395 & — & 1.0 & — \\ methylpyrazole & 110 & Nonanal & 124-19-6 & oily & MS, aroma, RI, S & 1396 & 1108 & — & 3.0 \\
11 & 2,3,5-Trimethylpyrazole & 14667-55-1 & earthy & MS, aroma, RI, S & 1410 & — & 3.3 & — \\
12 & 2-Octanol & 123-96-6 & soapy/creamy & MS, aroma, RI, S & 1412 & — & 3.5 & — \\
13 & (_E_)-2-Octonal & 2548-87-0 & grassy/fatty & MS, aroma, RI, S & 1429 & — & 2.5 & — \\
14 & Acetic acid & 64-19-7 & acetic & MS, aroma, RI, S & 1452 & — & 4.0 & — \\
15 & 1-Heptanol & 111-70-6 & grassy & MS, aroma, RI, S & 1452 & 980 & — & 2.5 \\
16 & 2-Ethyl-3,5- & 13925-07-0 & boiled potato & MS, aroma, RI, S & 1464 & 1085 & 4.0 & 2.5 \\ dimethylpyrazole & & & herbal & aroma & 1480 & — & 1.0 & — \\
17 & 18 & 2-Ethylhexanol & 104-76-7 & grassy & MS, aroma, RI, S & 1489 & — & 1.0 & — \\
19 & Benzaldehyde & 100-52-7 & bitter almond & MS, aroma, RI, S & 1508 & 961 & 3.7 & 2.0 \\
20 & (_E_)-2-Nonneal & 18829-56-6 & grassy/fatty & MS, aroma, RI, S & 1536 & — & 2.5 & — \\
21 & & minty & aroma & 1574 & — & 2.5 & — \\
22 & \(\beta\)-Carypbyllerene & 87-44-5 & woody & MS, aroma, RI, S & 1585 & — & 3.8 & — \\
23 & & wheat & aroma & 1602 & — & 2.5 & — \\
24 & Butanoic acid & 107-92-6 & sour and stinky & MS, aroma, RI, S & 1628 & — & 4.0 & — \\
25 & \(\gamma\)-Butylrolactone & 96-48-0 & wheat & MS, aroma, RI, S & 1643 & — & 2.3 & — \\
26 & Phenylacetaldehyde & 122-78-1 & penicillin/grassy & MS, aroma, RI, S & 1654 & 1044 & — & 3.0 \\
27 & Furfuryl alcohol & 98-00-0 & burnt/caramel & MS, aroma, RI, S & 1666 & — & 1.7 & — \\
28 & Ethyl benzoate & 93-89-0 & musly & MS, aroma, RI, S & 1672 & 1173 & 2.0 & 2.5 \\
29 & 3-Methylbutanoic acid & 503-74-2 & sour and stinky & MS, aroma, RI, S & 1680 & — & 4.0 & — \\
30 & Diethyl succinate & 123-25-1 & wheat/fruity & MS, aroma, RI, S & 1704 & — & 1.0 & — \\
31 & Naphthalene & 91-20-3 & grassy & MS, aroma, RI, S & 1750 & 1182 & — & 3.8 \\
32 & & herbal(powdery) & aroma & 1760 & — & 3.8 & — \\
33 & Ethyl phenylacetate & 101-97-3 & sweety & MS, aroma, RI, S & 1793 & 1247 & — & 2.0 \\
34 & 2,4-DecaIenal & 25152-84-5 & fatty/grassy & MS, aroma, RI, S & 1818 & 1316 & 2.0 & 2.2 \\
35 & 1-Phenylethanol & 98-85-1 & vanilla & MS, aroma, RI, S & 1820 & — & 1.5 & — \\
36 & & wheat & aroma & 1832 & — & 2.0 & — \\
37 & Geranyl acetone & 3796-70-1 & grassy & MS, aroma, RI, S & 1856 & 1453 & — & 2.5 \\
38 & & & bitter & aroma & 1857 & 1349 & 3.3 & 3.2 \\
39 & & & sweet & aroma & 1862 & 1390 & 3.0 & 3.5 \\
40 & Hexanoic acid & 142-62-1 & sour & MS, aroma, RI, S & 1866 & — & 3.2 & — \\
41 & Guaiacol & 90-05-1 & woody & MS, aroma, RI, S & 1871 & 1096 & 4.0 & 3.0 \\
42 & Benzyl alcohol & 100-51-6 & sweet/floral & MS, aroma, RI, S & 1877 & — & 2.5 & — \\
43 & Phenethyl alcohol & 60-12-8 & honey & MS, aroma, RI, S & 1901 & 1114 & 4.0 & 4.0 \\
44 & 2-Phenyl-2-butenal & 4411-89-6 & sweet & MS, aroma, RI, S & 1917 & — & 3.1 & — \\
45 & 4-Ethyl-2- & 2785-89-9 & clove & MS, aroma, RI, S & 2018 & 1279 & 4.0 & 3.5 \\  & methoxphenol & 104-61-0 & coconut & MS, aroma, RI, S & 2020 & 1368 & 4.0 & 2.8 \\
46 & \(\gamma\)- Nonanalactone & 106-44-5 & animal & MS, aroma, RI, S & 2078 & — & 3.0 & — \\
47 & 2-Methody-4 & 7786-61-0 & bake/bitter & MS, aroma, RI, S & 2184 & 1309 & 3.2 & 1.2 \\  & vinylphenol & 112-39-0 & wax & MS, aroma, RI, S & 2218 & 1929 & 4.0 & 3.9 \\
49 & Hexanal & 66-25-1 & fatty/grassy & MS, aroma, RI, S & 1078 & 838 & 3.1 & 2.0 \\ \hline \hline \end{tabular}  
*: NIST 11 was used to qualitative analysis, with matching degree \(\geq\) 80; RI: retention index; S: standard substance was used to qualitative analysis; b: Linear retention index of DB-wax; c: Linear retention index of HP-5.  
\end{table}