Table 1.
Volatile metabolites detected in alfalfa leaves using different SPME fibers at 50 °C for 20 min.
| RT a | RI b | Compound | PDMS | CAR/PDMS | DVB/CAR/PDMS |
|---|---|---|---|---|---|
| Alcohols | |||||
| 7.27 | 680 | 1-Penten-3-ol | 0.39 ± 0.05 c | N.D. | 6.09 ± 1.14 |
| 8.57 | 725 | 3-Methyl-1-butanol | N.D. | 1.12 ± 0.06 | N.D. |
| 8.84 | 734 | 2-Pentyn-1-ol | N.D. | 0.85 ± 0.18 | 0.22 ± 0.03 |
| 9.53 | 752 | (Z)-2-Penten-1-ol | N.D. | 8.26 ± 0.14 | 1.56 ± 0.63 |
| 12.02 | 827 | 2-Hexyn-1-ol | 0.49 ± 0.06 | N.D. | 7.51 ± 0.79 |
| 16.59 | 981 | 1-Octen-3-ol | 55.85 ± 9.49 | 386.22 ± 13.22 | 335.81 ± 26.62 |
| 19.43 | 1068 | (E)-2-Octen-1-ol | N.D. | 11.42 ± 8.32 | N.D. |
| Aldehydes | |||||
| 4.75 | 2-Propenal | N.D. | 0.45 ± 0.04 | 1.10 ± 0.19 | |
| 5.71 | 595 | Butanal | 0.04 ± 0.00 | 0.34 ± 0.11 | 0.28 ± 0.06 |
| 6.66 | 645 | 2-Butenal | N.D. | 0.92 ± 0.06 | 0.47 ± 0.01 |
| 7.62 | 700 | Pentanal | N.D. | N.D. | 0.26 ± 0.04 |
| 9.14 | 742 | 2-Pentenal | 0.19 ± 0.06 | 20.29 ± 4.31 | 8.31 ± 1.68 |
| 10.48 | 777 | 3-Hexenal | 3.14 ± 0.93 | 275.96 ± 42.84 | 270.77 ± 31.30 |
| 10.60 | 779 | Hexanal | 3.68 ± 0.86 | 192.41 ± 3.52 | 12.13 ± 1.27 |
| 12.40 | 837 | (E)-2-Hexenal | 25.72 ± 7.04 | 975.18 ± 40.25 | 332.79 ± 10.45 |
| 13.86 | 896 | Heptanal | N.D. | 1.13 ± 0.02 | 0.22 ± 0.11 |
| 14.14 | 908 | (E,E)-2,4-Hexadienal | N.D. | 48.24 ± 0.89 | 11.00 ± 1.45 |
| 16.08 | 967 | Benzaldehyde | N.D. | 0.65 ± 0.10 | 0.49 ± 0.05 |
| 17.64 | 1013 | (E,E)-2,4-Heptadienal | 0.09 ± 0.01 | 2.53 ± 0.26 | 1.32 ± 0.14 |
| 18.80 | 1049 | Benzeneacetaldehyde | N.D. | 0.77 ± 0.18 | 0.66 ± 0.06 |
| 20.62 | 1106 | Nonanal | 0.12 ± 0.02 | 0.42 ± 0.03 | 0.63 ± 0.04 |
| Ketones | |||||
| 4.78 | 2-Propanone | 0.22 ± 0.08 | 1.08 ± 0.08 | 5.60 ± 0.82 | |
| 5.65 | 587 | 2,3-Butanedione | N.D. | 0.66 ± 0.16 | 0.65 ± 0.10 |
| 7.32 | 683 | 1-Penten-3-one | 0.82 ± 0.04 | 85.48 ± 10.26 | 28.95 ± 6.68 |
| 7.55 | 696 | 3-Pentanone | N.D. | 128.27 ± 20.89 | 2.02 ± 0.44 |
| 16.42 | 978 | 1-Octen-3-one | 3.02 ± 1.22 | 84.21 ± 38.37 | 87.53 ± 10.67 |
| 20.29 | 3,5-Octadien-2-one | N.D. | 0.23 ± 0.05 | N.D. | |
| Terpenoids | |||||
| 5.02 | 508 | Isoprene | N.D. | 0.65 ± 0.15 | 0.34 ± 0.04 |
| 18.31 | 1034 | (+)-(R)-Limonene | N.D. | N.D. | 0.34 ± 0.01 |
| 19.66 | 1075 | cis-Linalool oxide | N.D. | N.D. | 0.47 ± 0.07 |
| 20.48 | 1100 | β-Linalool | N.D. | N.D. | 0.51 ± 0.01 |
| 3.22 | 1189 | p-Menth-1-en-4-ol | N.D. | N.D. | 0.66 ± 0.06 |
| 23.62 | 1203 | α-Terpinol | N.D. | N.D. | 0.13 ± 0.01 |
| 24.38 | 1229 | β-Cyclocitral | 0.13 ± 0.05 | 0.43 ± 0.07 | 0.20 ± 0.03 |
| 28.83 | 1388 | β-Damascenone | 0.11 ± 0.03 | N.D. | 0.29 ± 0.01 |
| Others | |||||
| 5.82 | 598 | 2-Methylfuran | N.D. | 0.45 ± 0.25 | N.D. |
| 7.66 | 701 | 2-Ethylfuran | 1.00 ± 0.44 | 109.48 ± 8.14 | 6.52 ± 0.59 |
| 12.76 | 893 | 3-Ethylthiophene | 0.28 ± 0.09 | 199.94 ± 25.38 | 4.12 ± 0.54 |
| 15.91 | 960 | 5-Ethyl-2(5H)-furanone | N.D. | 34.15 ± 6.35 | 25.34 ± 4.38 |
| 17.31 | 1003 | 3-Hexen-1-ol acetate | 0.36 ± 0.01 | 3.67 ± 0.15 | 1.96 ± 0.20 |
| 24.19 | 1222 | Ionene | N.D. | N.D. | 0.09 ± 0.01 |
| 31.42 | 1488 | β-Ionone | 1.51 ± 0.47 | 0.78 ± 0.17 | 1.14 ± 0.16 |
| Total known metabolites | 19 | 32 | 38 | ||
| Total volatile metabolites | 48 ± 3 | 99 ± 8 | 97 ± 5 | ||
a Retention time (min). b Retention index. c Mean area (×106) ± S.D. of three replicates; N.D., not detected.