Table 2.
Volatile metabolites were identified in different varieties of citrus peels by headspace-gas chromatography–ion mobility spectrometry.
| Class | Compound | CAS# | Formula | MW | RI | Rt [sec] | Dt [a.u.] |
|---|---|---|---|---|---|---|---|
| Alcohol | Nerolidol | 7212-44-4 | C15H26O | 222.4 | 1567.7 | 3059.1330 | 1.4866 |
| Ethanol(M) | 64-17-5 | C2H6O | 46.1 | 492.9 | 105.6470 | 1.0523 | |
| Ethanol(D) | 64-17-5 | C2H6O | 46.1 | 492.0 | 105.3950 | 1.1348 | |
| 1-Butanol(M) | 71-36-3 | C4H10O | 74.1 | 677.5 | 172.5980 | 1.1832 | |
| 1-Butanol(D) | 71-36-3 | C4H10O | 74.1 | 677.1 | 172.4280 | 1.3827 | |
| 1-Penten-3-ol | 616-25-1 | C5H10O | 86.1 | 694.6 | 182.1030 | 0.9443 | |
| 1-Nonanol | 143-08-8 | C9H20O | 144.3 | 1155.7 | 901.0090 | 1.5374 | |
| 1-heptanol | 111-70-6 | C7H16O | 116.2 | 964.9 | 498.5290 | 1.3931 | |
| 1-Hexanol(M) | 111-27-3 | C6H14O | 102.2 | 874.9 | 356.5090 | 1.3246 | |
| 1-Hexanol(D) | 111-27-3 | C6H14O | 102.2 | 877.1 | 359.2100 | 1.6411 | |
| 1-Pentanol | 71-41-0 | C5H12O | 88.1 | 768.6 | 244.5170 | 1.2554 | |
| Isopulegol | 89-79-2 | C10H18O | 154.3 | 1144.0 | 870.3370 | 1.3700 | |
| Isopulegol | 89-79-2 | C10H18O | 154.3 | 1144.0 | 870.3370 | 1.8998 | |
| Linalool(M) | 78-70-6 | C10H18O | 154.3 | 1108.9 | 784.3190 | 1.2245 | |
| Linalool(P) | 78-70-6 | C10H18O | 154.3 | 1107.0 | 779.8210 | 1.6940 | |
| Linalool(P) | 78-70-6 | C10H18O | 154.3 | 1106.2 | 777.9370 | 1.7592 | |
| Linalool(P) | 78-70-6 | C10H18O | 154.3 | 1107.8 | 781.7050 | 2.2372 | |
| alpha-Terpineol(M) | 98-55-5 | C10H18O | 154.3 | 1174.7 | 953.2470 | 1.2979 | |
| alpha-Terpineol(P) | 98-55-5 | C10H18O | 154.3 | 1176.2 | 957.4140 | 1.7866 | |
| 2-Methylpropan-1-ol M | 78-83-1 | C4H10O | 74.1 | 630.4 | 152.3040 | 1.1776 | |
| 2-Methylpropan-1-ol D | 78-83-1 | C4H10O | 74.1 | 629.2 | 151.7970 | 1.3611 | |
| (Z)-2-Penten-1-ol | 1576-95-0 | C5H10O | 86.1 | 762.5 | 238.6420 | 1.4511 | |
| Geraniol | 106-24-1 | C10H18O | 154.3 | 1246.9 | 1180.9060 | 1.2317 | |
| 2-Methyl-1-butanol M | 137-32-6 | C5H12O | 88.1 | 744.1 | 221.8530 | 1.2287 | |
| 2-Methyl-1-butanol D | 137-32-6 | C5H12O | 88.1 | 741.2 | 219.2900 | 1.4797 | |
| Aldehyde | Butanal | 123-72-8 | C4H8O | 72.1 | 601.3 | 140.9740 | 1.2896 |
| 2-Methylbutanal M | 96-17-3 | C5H10O | 86.1 | 664.7 | 166.8480 | 1.1663 | |
| 2-Methylbutanal D | 96-17-3 | C5H10O | 86.1 | 665.9 | 167.3550 | 1.4025 | |
| (E)-2-pentenal M | 1576-87-0 | C5H8O | 84.1 | 751.7 | 228.6410 | 1.1077 | |
| (E)-2-pentenal D | 1576-87-0 | C5H8O | 84.1 | 752.6 | 229.4380 | 1.3616 | |
| 3-Methyl-2-butenal M | 107-86-8 | C5H8O | 84.1 | 778.6 | 254.5330 | 1.0948 | |
| 3-Methyl-2-butenal D | 107-86-8 | C5H8O | 84.1 | 778.0 | 253.9220 | 1.3653 | |
| 1-Hexanal M | 66-25-1 | C6H12O | 100.2 | 788.7 | 264.3130 | 1.2610 | |
| 1-Hexanal D | 66-25-1 | C6H12O | 100.2 | 788.0 | 263.7020 | 1.5638 | |
| Heptanal-M | 111-71-7 | C7H14O | 114.2 | 902.2 | 393.1490 | 1.3265 | |
| Heptanal-D | 111-71-7 | C7H14O | 114.2 | 901.7 | 392.3500 | 1.7014 | |
| Octanal | 124-13-0 | C8H16O | 128.2 | 1017.0 | 597.0060 | 1.8263 | |
| Decanal M | 112-31-2 | C10H20O | 156.3 | 1190.9 | 1000.2970 | 1.5387 | |
| DecanaI D | 112-31-2 | C10H20O | 156.3 | 1188.4 | 992.6940 | 2.0484 | |
| Dodecanal | 112-54-9 | C12H24O | 184.3 | 1413.5 | 1936.1840 | 1.6544 | |
| Undecanal | 112-44-7 | C11H22O | 170.3 | 1285.9 | 1325.6690 | 1.5976 | |
| Furfural | 98-01-1 | C5H4O2 | 96.1 | 826.9 | 301.7580 | 1.0883 | |
| 2-Methylpropanal M | 78-84-2 | C4H8O | 72.1 | 561.1 | 126.6460 | 1.1141 | |
| 2-Methylpropanal D | 78-84-2 | C4H8O | 72.1 | 558.0 | 125.6400 | 1.2836 | |
| (E)-2-Hexenal M | 6728-26-3 | C6H10O | 98.1 | 851.6 | 328.7900 | 1.1833 | |
| (E)-2-Hexenal D | 6728-26-3 | C6H10O | 98.1 | 850.5 | 327.5900 | 1.5145 | |
| Nonanal(M) | 124-19-6 | C9H18O | 142.2 | 1100.4 | 764.6700 | 1.4795 | |
| Nonanal(D) | 124-19-6 | C9H18O | 142.2 | 1102.4 | 769.3210 | 1.9491 | |
| Pentanal M | 110-62-3 | C5H10O | 86.1 | 700.1 | 186.1440 | 1.1858 | |
| Pentanal D | 110-62-3 | C5H10O | 86.1 | 699.4 | 185.6130 | 1.4199 | |
| 2-Methyl-2-propenal M | 78-85-3 | C4H6O | 70.1 | 568.1 | 129.0400 | 1.0512 | |
| 2-Methyl-2-propenal D | 78-85-3 | C4H6O | 70.1 | 571.9 | 130.3680 | 1.2287 | |
| 3-Methylbutanal M | 590-86-3 | C5H10O | 86.1 | 650.3 | 160.5910 | 1.1832 | |
| 3-Methylbutanal D | 590-86-3 | C5H10O | 86.1 | 651.5 | 161.0980 | 1.4025 | |
| Ester | Geranyl acetate | 105-87-3 | C12H20O2 | 196.3 | 1384.3 | 1775.2690 | 1.2161 |
| Neryl acetate | 141-12-8 | C12H20O2 | 196.3 | 1358.5 | 1644.6450 | 1.2262 | |
| Butyl isovalerate | 109-19-3 | C9H18O2 | 158.2 | 1028.3 | 617.4230 | 1.8877 | |
| Acetic acid ethyl ester(M) | 141-78-6 | C4H8O2 | 88.1 | 607.2 | 143.1720 | 1.0938 | |
| Acetic acid ethyl ester(D) | 141-78-6 | C4H8O2 | 88.1 | 604.0 | 141.9880 | 1.3329 | |
| Ethyl butanoate | 105-54-4 | C6H12O2 | 116.2 | 810.0 | 284.5660 | 1.2097 | |
| Isobutyl acetate | 110-19-0 | C6H12O2 | 116.2 | 780.0 | 255.8990 | 1.6067 | |
| 2-nonynoic acid methyl ester | 111-80-8 | C10H16O2 | 168.2 | 1297.2 | 1371.0250 | 1.4670 | |
| Ketone | Carvone (M) | 99-49-0 | C10H14O | 150.2 | 1207.6 | 1050.9830 | 1.3112 |
| Carvone (D) | 99-49-0 | C10H14O | 150.2 | 1220.3 | 1091.5320 | 1.8166 | |
| 1-Penten-3-one | 1629-58-9 | C5H8O | 84.1 | 688.4 | 177.7240 | 1.0825 | |
| 2-Butanone(M) | 78-93-3 | C4H8O | 72.1 | 595.0 | 138.6060 | 1.0647 | |
| 2-Butanone(D) | 78-93-3 | C4H8O | 72.1 | 595.0 | 138.6060 | 1.2444 | |
| 2-Pentanone | 107-87-9 | C5H10O | 86.1 | 689.1 | 178.1790 | 1.1206 | |
| Cyclohexanone(M) | 108-94-1 | C6H10O | 98.1 | 894.8 | 382.2440 | 1.1547 | |
| Cyclohexanone(D) | 108-94-1 | C6H10O | 98.1 | 896.0 | 384.0630 | 1.4492 | |
| 2-Heptanone M | 110-43-0 | C7H14O | 114.2 | 888.5 | 373.6670 | 1.2627 | |
| 2-Heptanone D | 110-43-0 | C7H14O | 114.2 | 889.3 | 374.7070 | 1.6190 | |
| 2-Hexanone M | 591-78-6 | C6H12O | 100.2 | 779.8 | 255.7320 | 1.1909 | |
| 2-Hexanone D | 591-78-6 | C6H12O | 100.2 | 780.3 | 256.2640 | 1.5039 | |
| Acetone | 67-64-1 | C3H6O | 58.1 | 509.3 | 110.3700 | 1.1184 | |
| 3-Hydroxy-2-butanone | 513-86-0 | C4H8O2 | 88.1 | 711.7 | 194.9390 | 1.3274 | |
| 2,3-Butanedione | 431-03-8 | C4H6O2 | 86.1 | 581.8 | 133.8480 | 1.1803 | |
| Terpenes | farnesene-(M) | 502-61-4 | C15H24 | 204.4 | 1500.1 | 2502.9580 | 1.4332 |
| farnesene-(P) | 502-61-4 | C15H24 | 204.4 | 1506.9 | 2553.7280 | 1.4742 | |
| p-mentha-1,5-diene | 99-83-2 | C10H16 | 136.2 | 1008.2 | 581.6800 | 1.6828 | |
| Myrcene(M) | 123-35-3 | C10H16 | 136.2 | 993.5 | 555.5820 | 1.2750 | |
| Myrcene(P) | 123-35-3 | C10H16 | 136.2 | 993.9 | 556.3340 | 1.7116 | |
| Myrcene(P) | 123-35-3 | C10H16 | 136.2 | 994.1 | 556.7100 | 1.9191 | |
| Myrcene(P) | 123-35-3 | C10H16 | 136.2 | 994.1 | 556.7100 | 2.1439 | |
| alpha-Pinene(M) | 80-56-8 | C10H16 | 136.2 | 936.5 | 447.5680 | 1.2155 | |
| alpha-Pinene(P) | 80-56-8 | C10H16 | 136.2 | 935.1 | 445.2690 | 1.2942 | |
| alpha-Pinene(P) | 80-56-8 | C10H16 | 136.2 | 936.8 | 448.1420 | 1.6690 | |
| alpha-Pinene(P) | 80-56-8 | C10H16 | 136.2 | 932.7 | 441.2470 | 1.7313 | |
| gamma-Terpinene(M) | 99-85-4 | C10H16 | 136.2 | 1068.4 | 695.4080 | 1.2152 | |
| gamma-Terpinene(P) | 99-85-4 | C10H16 | 136.2 | 1067.6 | 693.7680 | 1.6973 | |
| Limonene M | 138-86-3 | C10H16 | 136.2 | 1041.1 | 641.3330 | 1.2105 | |
| Limonene P | 138-86-3 | C10H16 | 136.2 | 1039.6 | 638.5680 | 1.2887 | |
| Limonene P | 138-86-3 | C10H16 | 136.2 | 1039.6 | 638.5680 | 1.6622 | |
| Limonene P | 138-86-3 | C10H16 | 136.2 | 1041.1 | 641.3330 | 1.7228 | |
| Limonene P | 138-86-3 | C10H16 | 136.2 | 1043.1 | 645.2050 | 2.1628 | |
| beta-Pinene(M) | 127-91-3 | C10H16 | 136.2 | 975.7 | 519.2280 | 1.2161 | |
| beta-Pinene(P) | 127-91-3 | C10H16 | 136.2 | 975.9 | 519.7380 | 1.6290 | |
| beta-Pinene(P) | 127-91-3 | C10H16 | 136.2 | 973.1 | 514.1280 | 1.7175 | |
| beta-Pinene(P) | 127-91-3 | C10H16 | 136.2 | 973.8 | 515.6580 | 2.1624 | |
| beta-Pinene(P) | 127-91-3 | C10H16 | 136.2 | 972.5 | 513.1080 | 2.5680 | |
| Sulfur compounds | beta-Ionene | 14901-07-6 | C13H20O | 192.3 | 1485.4 | 2396.1810 | 1.4736 |
| others | Dimethyl sulfide | 75-18-3 | C2H6S | 62.1 | 541.1 | 120.1070 | 0.9631 |
| (1r,4r)-(+)-campho | 464-49-3 | C10H16O | 152.2 | 1144.4 | 871.2550 | 1.8639 |