## 3 Results and Discussion
### Analysis of Aroma Active Compounds in Xiaoqu Liquor
** & **Compounds** & **Quantitative Ion** & **Linear Equation** & **R2** & **Threshold \(\mu\)g/L** & **Content \(\mu\)g/L** \\ \hline
21 & N-hexanol \({}^{\text{a}}\) & 56 & Y = 0.0368\(\pm\) 0.0094 & 0.9999 & 5370.00 [19] & 1200.1 \(\pm\) 81.22 \\
22 & Ethyl heptanoate \({}^{\text{a}}\) & 88 & Y = 1.9144\(\pm\) 0.0224 & 0.9999 & 13,153.17 [17] & 118.86 \(\pm\) 15.43 \\
23 & 2-nonanone \({}^{\text{a}}\) & 71 & Y = 0.351\(\pm\) 0.0015 & 0.9999 & 2000.000 [19] & 17.8 \(\pm\) 3.43 \\
24 & Trans-2-hexene-1-ol & 57 & Y = 0.0886\(\pm\) 0.2365 & 0.9967 & - & 15.9 \(\pm\) 4.43 \\
25 & 3-hydroxy-2-butanone & 45 & Y = 0.9168\(\pm\) 0.0381 & 0.9957 & - & 16.87 \(\pm\) 2.41 \\
26 & Ethyl caprylate \({}^{\text{a}}\) & 88 & Y = 3.5369\(\pm\) 0.1477 & 0.9993 & 12.87 [16] & 5002.82 \(\pm\) 300.25 \\
27 & Acetic acid \({}^{\text{b}}\) & - & Y = 0.1933\(\pm\) 0.1712 & 0.9927 & 160,000.00 [17] & 526,890 \(\pm\) 5436.87 \\
28 & Furfural \({}^{\text{a}}\) & 96 & Y = 0.0164\(\pm\) 0.0214 & 0.9996 & 44,029.73 [17] & 7440.7 \(\pm\) 633.21 \\
29 & 1-octen-3-ol \({}^{\text{a}}\) & 72 & Y = 0.1788\(\pm\) 0.0761 & 0.9999 & 6.12 [17] & 127.3 \(\pm\) 11.54 \\
30 & Benzaldehyde \({}^{\text{a}}\) & 106 & Y = 0.0696\(\pm\) 0.1094 & 0.9998 & 4200.00 [17] & 379.6 \(\pm\) 31.01 \\
31 & Ethyl nonanoate \({}^{\text{a}}\) & 88 & Y = 4.5654\(\pm\) 0.4416 & 0.9994 & 3150.61 [17] & 59.99 \(\pm\) 22.55 \\
32 & Propionic acid \({}^{\text{b}}\) & - & Y = 0.3754\(\pm\) 0.0127 & 0.9956 & 18.200 [17] & 44,000.3879.54 \\
33 & Ethyl caprate \({}^{\text{a}}\) & 88 & Y = 11.147\(\pm\) 0.1139 & 0.9997 & 1122.30 [17] & 563.878 \(\pm\) 453.33 \\
34 & Butyric acid \({}^{\text{b}}\) & - & Y = 0.5299\(\pm\) 0.0148 & 0.9977 & 964.00 [17] & 8590 \(\pm\) 598.45 \\
35 & Phenylacetaldehyde \({}^{\text{a}}\) & 91 & Y = 0.0318\(\pm\) 0.0185 & 0.9998 & 262.00 [17] & 2371.58 \(\pm\) 54.76 \\
36 & 1-nonanol \({}^{\text{a}}\) & 70 & Y = 0.1021\(\pm\) 0.0705 & 0.9994 & 80.00 [20] & 300.6 \(\pm\) 21.25 \\
37 & Isovaleric acid \({}^{\text{a}}\) & - & Y = 0.4347\(\pm\) 0.0165 & 0.9903 & 1050.00 [19] & 7900 \(\pm\) 66.34 \\
38 & Ethyl benzoate \({}^{\text{a}}\) & 105 & Y = 5.3927\(\pm\) 1.871 & 0.9972 & 1430.00 [17] & 13.96 \(\pm\) 5.43 \\
39 & Diethyl succinate \({}^{\text{a}}\) & 101 & Y = 0.0655\(\pm\) 0.0935 & 0.9973 & 353,193.2 [17] & 274.48 \(\pm\) 1153.43 \\
40 & 2-diphoene formaldehyde & 111 & Y = 0.2458\(\pm\) 0.1877 & 0.9996 & - & 42.54 \(\pm\) 1.64 \\
41 & Ethyl undecanoate \({}^{\text{a}}\) & 88 & Y = 3.1092\(\pm\) 0.0019 & 0.9999 & 1000.00 [20] & 15.5 \(\pm\) 1.44 \\
42 & Valeric acid \({}^{\text{b}}\) & - & Y = 0.5067\(\pm\) 0.0144 & 0.996 & 389.00 [17] & 11,750 \(\pm\) 435.76 \\
43 & Ethyl phenylacetate \({}^{\text{a}}\) & 91 & Y = 3.8931\(\pm\) 0.3535 & 0.9996 & 406.83 [17] & 71.35 \(\pm\) 22.14 \\
44 & Phenethyl acetate \({}^{\text{a}}\) & 104 & Y = 0.5614\(\pm\) 0.5711 & 0.9995 & 909.00 [17] & 1927.65 \(\pm\) 132.43 \\
45 & Ethyl laurate \({}^{\text{a}}\) & 88 & Y = 13.156\(\pm\) 7.4179 & 0.9836 & 400.00 [20] & 2827.21 \(\pm\) 212.45 \\
46 & Hexanoic acid \({}^{\text{b}}\) & - & Y = 0.7798\(\pm\) 0.0158 & 0.9973 & 2520.00 [17] & 4950 \(\pm\) 445.65 \\
47 & Ethyl phenylpropionate \({}^{\text{a}}\) & 104 & Y = 45.928\(\pm\) 0.5711 & 0.9996 & 1250.00 [17] & 68.75 \(\pm\) 13.54 \\
48 & Phenethyl alcohol \({}^{\text{a}}\) & 91 & Y = 0.0217\(\pm\) 0.001 & 0.9999 & 28,922.73 [17] & 33,223.98 \(\pm\) 2341.60 \\
49 & Hepatanoic acid \({}^{\text{b}}\) & - & Y = 0.5468\(\pm\) 0.0165 & 0.9999 & - & 5157 \(\pm\) 413.54 \\
50 & 4-methylguaiocal \({}^{\text{a}}\) & 138 & Y = 0.0545\(\pm\) 0.0268 & 0.999 & 314.56 [17] & 252.8 \(\pm\) 15.87 \\
51 & Ethyl myristate \({}^{\text{a}}\) & 88 & Y = 17.385\(\pm\) 0.3862 & 0.9973 & 180.00 [17] & 1721.8 \(\pm\) 23.46 \\
52 & 4-ethylgaiaiaacol \({}^{\texttaste), ethyl hexanoate (sweet aroma, fruity aroma, and cellar aroma), ethyl valerate, ethyl isovalerate, and ethyl butyrate [18; 19]. The aldehyde compounds with great contributions to the aroma of Xiaoqu liquor were acetaldehyde and acetal.