Table 3.
Nonvolatile metabolites annotated in various citrus peels via ultra-high-performance liquid chromatography–Q-Orbitrap high-resolution mass spectrometry using both the positive and negative ionization modes.
| No. | tR/min | compounds | Molecular Formula | m/z | [M−H]−/[M + H]+ | Mass Error (ppm) | HR-MS/MS Product Ions (m/z) | Chemical Class |
|---|---|---|---|---|---|---|---|---|
| 1 | 1.236 | L-Histidine | C6H9N3O2 | 156.07699 | 155.06963[M+H]+1 | +1.01 | 156.07695,110.07171,95.06095 | Carboxylic acids and derivatives |
| 2 | 1.257 | DL-Arginine | C6H14N4O2 | 173.104 | 174.11184[M-H]-1 | +0.96 | 175.11951,116.07106,70.06589 | Carboxylic acids and derivatives |
| 3 | 1.259 | Choline | C5H13NO | 104.10745 | 103.10018[M+H]+1 | +4.48 | 104.10750,87.04470,60.08154 | Others |
| 4 | 1.273 | Aspartic acid | C4H7NO4 | 134.04494 | 133.03766[M+H]+1 | +1.14 | 88.03992,74.02437,75.02769 | Carboxylic acids and derivatives |
| 5 | 1.326 | D-(+)-Proline | C5H9NO2 | 116.07092 | 115.06364[M+H]+1 | +2.72 | 116.07095,70.06583 | Carboxylic acids and derivatives |
| 6 | 1.342 | L(−)-Pipecolinic acid | C6H11NO2 | 130.08642 | 129.07914[M+H]+1 | +1.26 | 130.08653,84.08143 | Carboxylic acids and derivatives |
| 7 | 1.402 | Phloroglucinol | C6H6O3 | 127.03919 | 126.03191[M+H]+1 | +1.71 | 127.03927,109.02886,81.03418 | Others |
| 8 | 1.41 | Synephrine | C9H13NO2 | 168.10203 | 167.09475[M+H]+1 | +0.72 | 150.09158,135.06812,91.05485 | Others |
| 9 | 1.421 | D-(+)-Malic acid | C4H6O5 | 133.01352 | 134.0208[M-H]-1 | −5.41 | 133.01363,115.00294,72.99220,71.01292 | Others |
| 10 | 1.456 | 2-Furoic acid | C5H4O3 | 111.00797 | 112.01527[M-H]-1 | −6.91 | 111.00803,83.01294,78.95819,67.01799 | Others |
| 11 | 1.499 | L-Tyrosine | C9H11NO3 | 182.08151 | 181.07424[M+H]+1 | +1.89 | 164.05484,136.07587,123.04435 | Carboxylic acids and derivatives |
| 12 | 1.703 | Betaine | C5H11NO2 | 118.08667 | 117.0794[M+H]+1 | +3.57 | 118.08659,72.08419,59.07371 | Carboxylic acids and derivatives |
| 13 | 1.713 | Nicotinic acid | C6H5NO2 | 124.0396 | 123.03232[M+H]+1 | +2.36 | 140.03438,124.03957,96.04493 | Others |
| 14 | 1.729 | Citric acid | C6H8O7 | 210.061 | 192.02688[M + NH4]+1 | −0.66 | 191.01956,111.00803,87.00790,85.02863 | Carboxylic acids and derivatives |
| 15 | 1.735 | 4-Oxoproline | C5H7NO3 | 128.03465 | 129.04227[M-H]-1 | −2.49 | 128.03462,82.02896, | Carboxylic acids and derivatives |
| 16 | 1.949 | Isoleucine | C6H13NO2 | 132.10224 | 131.09496[M+H]+1 | +2.52 | 90.94827,86.09702,72.93781,69.07069 | Carboxylic acids and derivatives |
| 17 | 1.96 | Succinic acid | C4H6O4 | 117.01867 | 118.02595[M-H]-1 | −5.62 | 117.01852,99.00787,73.02851 | Carboxylic acids and derivatives |
| 18 | 3.242 | L-Phenylalanine | C9 H11NO2 | 164.07136 | 165.07912[M-H]-1 | +0.87 | 120.08101,107.04958,103.05463 | Carboxylic acids and derivatives |
| 19 | 6.604 | D-(+)-Tryptophan | C11H12N2O2 | 203.08253 | 204.09013[M-H]-1 | +1.26 | 188.07077,146.06018,118.06548 | Others |
| 20 | 7.622 | Caffeic acid | C9H8O4 | 181.04975 | 180.04247[M+H]+1 | +1.20 | 163.3918,145.02867,135.04433 | Cinnamic acids and derivatives |
| 21 | 7.808 | 4-Coumaric acid | C9H8O3 | 165.05491 | 164.04763[M+H]+1 | +1.73 | 147.04422,119.0495091.05483 | Cinnamic acids and derivatives |
| 22 | 9.988 | Isoferulic acid | C10H10O4 | 195.06542 | 194.05814[M+H]+1 | +1.19 | 177.05481,145.02858,117.03384 | Cinnamic acids and derivatives |
| 23 | 10.155 | Sinapinic acid | C11H12O5 | 207.06546 | 206.05817[M+H]+1 | +0.94 | 207.06557,175.03925,147.04422 | Cinnamic acids and derivatives |
| 24 | 10.923 | Narirutin | C27H32O14 | 581.18669 | 580.17941[M+H]+1 | +0.36 | 273.07590,195.02898,153.01839,85.02901 | Flavonoids |
| 25 | 12.175 | Fisetin | C15H10O6 | 287.0549 | 286.04762[M+H]+1 | −0.41 | 287.05511,153.01833,135.04404 | Flavonoids |
| 26 | 12.367 | Hyperoside | C21H20O12 | 463.08909 | 464.09632[M-H]-1 | +1.81 | 303.05020,153.01839,85.02904 | Flavonoids |
| 27 | 12.947 | Isorhamnetin | C16H12O7 | 317.06573 | 316.05846[M+H]+1 | +0.49 | 317.06570,302.04224,153.01842 | Flavonoids |
| 28 | 13.003 | Rhoifolin | C27H30O14 | 579.17112 | 578.16397[M+H]+1 | +0.72 | 433.11346,271.06021,153.01846 | Flavonoids |
| 29 | 13.008 | Naringin | C15H12O5 | 273.07569 | 272.06841[M+H]+1 | +0.39 | 273.07587,171.02887,153.01834,147.04417 | Flavonoids |
| 30 | 13.008 | Naringeninchalcone | C27H32O14 | 579.17232 | 580.17943[M-H]-1 | −0.25 | 273.07587,171.02887,153.01834,147.04417 | Flavonoids |
| 31 | 13.362 | Diosmetin | C28H32O15 | 609.18206 | 608.17486[M+H]+1 | −0.22 | 463.12402,301.07089,286.04742 | Flavonoids |
| 32 | 13.55 | Hesperidin | C28H34O15 | 609.18312 | 610.18998[M-H]-1 | +0.34 | 303.08636,153.01833,85.02896 | Flavonoids |
| 33 | 13.551 | Hesperetin | C16H14O6 | 303.08626 | 302.07894[M+H]+1 | −0.33 | 303.08640,177.05472,153.01831 | Flavonoids |
| 34 | 13.664 | Homoplantaginin | C22H22O11 | 463.12372 | 462.11653[M+H]+1 | +0.70 | 301.07089,286.04742,258.5258 | Flavonoids |
| 35 | 13.85 | Neohesperidin | C28H34O15 | 609.1839 | 610.19112[M-H]-1 | +2.22 | 609.18396,301.07214,151.00313 | Flavonoids |
| 36 | 14.363 | Scoparone | C11H10O4 | 207.06551 | 206.05823[M+H]+1 | +1.57 | 207.06523,192.04176,151.07545 | Coumarins and derivatives |
| 37 | 15.788 | Pinocembrin | C15H12O4 | 257.08102 | 256.07375[M+H]+1 | +0.74 | 257.08150,171.02901,153.01846,131.04939 | Flavonoids |
| 38 | 18.033 | Isokaempferide | C16H12O6 | 299.05649 | 300.06372[M-H]-1 | +1.09 | 301.07086,286.04736,258.05280 | Flavonoids |
| 39 | 18.26 | Genistein | C15H10O5 | 269.04605 | 270.05331[M-H]-1 | +1.81 | 271.06027,153.01822,119.04935 | Flavonoids |
| 40 | 18.287 | Naringenin | C15H12O5 | 271.06179 | 272.06904[M-H]-1 | +2.09 | 271.06174,151.00311,119.04951 | Flavonoids |
| 41 | 18.518 | Hispidulin | C16H12O6 | 299.05646 | 300.06373[M-H]-1 | +1.14 | 299.05655,284.03308,136.98741 | Flavonoids |
| 42 | 20.216 | Moxonidine | C9H12ClN5O | 240.06686 | 241.07413[M-H]-1 | +4.55 | 242.08118,227.05780,200.07069 | Others |
| 43 | 22.123 | Monobutyl phthalate | C12H14O4 | 221.08195 | 222.08922[M-H]-1 | +0.06 | 221.08167,121.02860,71.04923 | Others |
| 44 | 22.24 | Tangeritin | C20H20O7 | 373.12855 | 372.12126[M+H]+1 | +0.97 | 373.12814,357.09683,343.08121 | Flavonoids |
| 45 | 22.373 | Scrophulein | C17H14O6 | 315.08661 | 314.07948[M+H]+1 | +1.40 | 315.08652,282.05246,254.05754 | Flavonoids |
| 46 | 23.77 | Limonin | C26H30O8 | 471.20206 | 470.19474[M+H]+1 | +1.44 | 471.20306,425.19720,161.06006 | Others |
| 47 | 24.709 | Nobiletin | C21H22O8 | 403.1392 | 402.13192[M+H]+1 | +1.14 | 403.13907,373.09204,183.02911 | Flavonoids |
| 48 | 25.003 | 6-Demethoxytangeretin | C19H18O6 | 343.11795 | 342.11067[M+H]+1 | +0.98 | 343.11777,313.07074,299.09158 | Flavonoids |
| 49 | 25.404 | Skullcapflavone II | C19H18O8 | 375.10771 | 374.10048[M+H]+1 | +0.84 | 375.10706,345.06061,327.05011 | Flavonoids |
| 50 | 28.806 | Eupatilin | C18H16O7 | 345.0975 | 344.09022[M+H]+1 | +1.80 | 345.09720,330.07339,329.06473 | Flavonoids |
| 51 | 33.685 | Osthol | C15H16O3 | 245.11773 | 244.11045[M+H]+1 | +2.09 | 245.11766,189.05495,131.04945 | Coumarins and derivatives |
| 52 | 37.289 | Nootkatone | C15H22O | 219.17459 | 218.16731[M+H]+1 | +1.14 | 219.17464,163.11180,81.07054 | Others |
| 53 | 37.741 | Hexadecanamide | C16H33NO | 256.26331 | 255.25603[M+H]+1 | −0.73 | 256.26309,153.65048,88.07630 | Others |