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. 2021 Jan 20;10(2):151. doi: 10.3390/antiox10020151

Table 3.

Characterization of phenolic compounds in different pear samples by liquid chromatography coupled with electrospray-ionization quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF-MS/MS).

No. Molecular Formula Proposed Compounds RT (min) Ionization (ESI+/ESI−) Molecular Weight Theoretical (m/z) Observed (m/z) Error (ppm) MS2 Production Pears
Phenolic acid
Hydroxybenzoic Acids
1 C8H8O7S Vanillic acid 4-sulfate 5.122 [M − H] − 247.9991 246.9918 246.9915 −1.2 167 BB
2 C13H16O10 Gallic acid 4-O-glucoside 6.731 [M − H] − 332.0743 331.067 331.0675 1.5 169, 125 * RI, BB, JM
3 C7H6O5 Gallic acid 6.878 [M − H] − 170.0215 169.0142 169.0145 1.8 125 BB
4 C13H16O9 Protocatechuic acid 4-O-glucoside 7.524 [M − H] − 316.0794 315.0721 315.0718 −1.0 153 * BB, RI, JM, PT
5 C7H6O3 2-Hydroxybenzoic acid 11.185 [M − H] − 138.0317 137.0244 137.025 4.4 93 * BB, JM, RI, PT
6 C13H16O8 4-Hydroxybenzoic acid 4-O-glucoside 11.218 [M − H] − 300.0845 299.0772 299.0759 −4.3 255, 137 * BB, WN
7 C14H10O9 Gallic acid 3-O-gallate 17.066 [M − H] − 322.0325 321.0252 321.0239 −4.0 169 BB
8 C7H6O4 2,3-Dihydroxybenzoic acid 24.242 [M − H] − 154.0266 153.0193 153.0192 −0.7 109 * RI, JM
Hydroxycinnamic Acids
9 C9H8O3 m-Coumaric acid 5.207 [M − H] − 164.0473 163.04 163.0397 −1.8 119 * RI, JM, PT
10 C9H8O2 Cinnamic acid 9.219 ** [M − H] − 148.0524 147.0451 147.0461 4.8 103 * WN, RI, PT, BB
11 C14H14O9 Feruloyl tartaric acid 10.506 [M − H] − 326.0638 325.0565 325.0567 0.6 193, 149 BB
12 C9H8O4 Caffeic acid 12.932 ** [M − H] − 180.0423 179.035 179.0346 −2.2 143, 133 * JM, BB, RI
13 C15H16O10 Caffeic acid 3-O-glucuronide 13.308 [M − H] − 356.0743 355.067 355.0672 0.6 179 RI
14 C15H18O8 p-Coumaric acid 4-O-glucoside 14.962 [M − H] − 326.1002 325.0929 325.0911 −5.5 163 BB
15 C15H18O9 Caffeoyl glucose 19.343 [M − H] − 342.0951 341.0878 341.0865 −3.8 179, 161 * JM, PT
16 C16H18O9 3-Caffeoylquinic acid 24.793 [M − H] − 354.0951 353.0878 353.0865 −3.7 253, 190, 144 JM
17 C16H18O10 Ferulic acid 4-O-glucuronide 26.748 [M − H] − 370.09 369.0827 369.0838 3.0 193 JM
18 C16H18O8 3-p-Coumaroylquinic acid 27.825 [M − H] − 338.1002 337.0929 337.0918 −3.3 265, 173, 162 JM
19 C13H12O8 p-Coumaroyl tartaric acid 28.947 ** [M − H] − 296.0532 295.0459 295.0457 −0.7 115 * RI, BB
20 C17H20O9 3-Feruloylquinic acid 29.432 ** [M − H] − 368.1107 367.1034 367.1028 −1.6 298, 288, 192, 191 * JM, BB, WN
21 C16H20O9 Ferulic acid 4-O-glucoside 33.867 [M − H] − 356.1107 355.1034 355.1039 1.4 193, 178, 149, 134 RI
22 C10H10O4 Ferulic acid 38.378 [M − H] − 194.0579 193.0506 193.0499 −3.6 178, 149, 134 JM
23 C18H16O8 Rosmarinic acid 39.746 [M − H] − 360.0845 359.0772 359.0773 0.3 179 BB
24 C25H24O12 1,5-Dicaffeoylquinic acid 45.17 [M − H] − 516.1268 515.1195 515.1176 −3.7 353, 335, 191, 179 JM
25 C15H18O7 Cinnamoyl glucose 60.985 [M − H] − 310.1053 309.098 309.0965 −4.9 147, 131, 103 BB
Hydroxyphenylacetic Acids
26 C8H8O4 3,4-Dihydroxyphenylacetic acid 10.011 [M − H] − 168.0423 167.035 167.0349 −0.6 149, 123 * RI, BB, WN, JM
27 C8H8O3 2-Hydroxy-2-phenylacetic acid 10.821 [M − H] − 152.0473 151.04 151.0405 3.3 136, 92 BB
Hydroxyphenylpropanoic Acids
28 C9H10O4 3-Hydroxy-3-(3-hydroxyphenyl) propionic acid 14.73 [M − H] − 182.0579 181.0506 181.0504 −1.1 163, 135, 119 BB
29 C15H18O10 Dihydrocaffeic acid 3-O-glucuronide 20.796 [M − H] − 358.09 357.0827 357.0828 0.3 181 * RI, BB
30 C16H20O10 Dihydroferulic acid 4-O-glucuronide 29.117 [M − H] − 372.1056 371.0983 371.0975 −2.2 195 JM
Flavonoid
Anthocyanins
31 C24H25O13 Petunidin 3-O-(6’’-acetyl-glucoside) 27.386 [M + H]+ 521.1295 522.1368 522.1358 −1.9 317 WN
32 C43H49O24 Cyanidin 3-O-(2-O-(6-O-(E)-caffeoyl-D glucoside)-D-glucoside)-5-O-D-glucoside 40.107 [M + H]+ 949.2614 950.2687 950.2673 −1.5 787, 463, 301 BB
Dihydrochalcones
33 C21H24O11 3-Hydroxyphloretin 2’-O-glucoside 13.819 [M − H] − 452.1319 451.1246 451.1236 −2.2 289, 273 BB
34 C26H32O15 3-Hydroxyphloretin 2’-O-xylosyl-glucoside 36.847 [M − H] − 584.1741 583.1668 583.1677 1.5 289 * BB, RI
Dihydroflavonols
35 C15H12O7 Dihydroquercetin 11.732 [M − H] − 304.0583 303.051 303.0501 −3.0 285, 275, 151 BB
36 C21H22O12 Dihydromyricetin 3-O-rhamnoside 34.071 [M − H] − 466.1111 465.1038 465.1044 1.3 301 JM
Flavanols
37 C15H14O7 (+)-Gallocatechin 4.676 [M − H] − 306.074 305.0667 305.0676 3.0 261, 219 * PT, BB
38 C22H24O13 4’-O-Methyl-(-)-epigallocatechin 7-O-glucuronide 6.911 [M − H] − 496.1217 495.1144 495.1153 1.8 451, 313 BB
39 C30H26O12 Procyanidin dimer B1 23.22 [M − H] − 578.1424 577.1351 577.1318 −5.7 451 JM
40 C16H16O6 3’-O-Methylcatechin 24.124 [M − H] − 304.0947 303.0874 303.0878 1.3 271, 163 BB
41 C15H14O6 (+)-Catechin 26.351 [M − H] − 290.079 289.0717 289.0712 −1.7 245, 205, 179 * JM, BB
42 C45H38O18 Procyanidin trimer C1 28.687 [M − H] − 866.2058 865.1985 865.1941 −5.1 739, 713, 695 JM
43 C22H18O10 (+)-Catechin 3-O-gallate 36.333 [M − H] − 442.09 441.0827 441.0825 −0.5 289, 169, 125 BB
Flavanones
44 C28H30O18 Hesperetin 3’,7-O-diglucuronide 9.315 [M − H] − 654.1432 653.1359 653.1362 0.5 477, 301, 286, 242 RI
45 C22H22O12 Hesperetin 3’-O-glucuronide 47.368 [M − H] − 478.1111 477.1038 477.1022 −3.4 301, 286, 257, 242 PT
Flavones
46 C27H30O14 Rhoifolin 27.229 [M − H] − 578.1636 577.1563 577.1538 −4.3 413, 269 JM
47 C27H30O15 Apigenin 6,8-di-C-glucoside 42.901 ** [M − H] − 594.1585 593.1512 593.1485 −4.6 503, 473 * JM, WN
48 C21H20O11 6-Hydroxyluteolin 7-O-rhamnoside 46.341 ** [M − H] − 448.1006 447.0933 447.0915 −4.0 301 * PT, JM, WN, BB
49 C15H10O4 7,4’-Dihydroxyflavone 82.529 [M + H]+ 254.0579 255.0652 255.0646 −2.4 227, 199, 171 * RI, BB
Flavonols
50 C21H20O13 Myricetin 3-O-galactoside 19.288 [M − H] − 480.0904 479.0831 479.081 −4.4 317 PT
51 C27H30O17 Myricetin 3-O-rutinoside 31.52 [M − H] − 626.1483 625.141 625.1386 −3.8 301 JM
52 C43H48O24 Spinacetin 3-O-(2’’-p-coumaroylglucosyl) (1->6)- [apiosyl (1->2)]-glucoside 33.242 [M − H] − 948.2536 947.2463 947.2456 −0.7 741, 609, 301 JM
53 C33H40O19 Kaempferol 3-O-(2’’-rhamnosyl-galactoside) 7-O-rhamnoside 35.077 [M − H] − 740.2164 739.2091 739.2091 0.0 593, 447, 285 RI
54 C27H30O16 Kaempferol 3,7-O-diglucoside 37.384 [M − H] − 610.1534 609.1461 609.1453 −1.3 447, 285 * JM, RI
55 C33H40O20 Kaempferol 3-O-glucosyl-rhamnosyl-galactoside 40.184 ** [M − H] − 756.2113 755.204 755.2047 0.9 285 * JM, WN, RI
56 C21H20O12 Myricetin 3-O-rhamnoside 40.234 [M − H] − 464.0955 463.0882 463.0882 0.0 317 * JM, PT
Isoflavonoids
57 C15H12O4 2-Dehydro-O-desmethylangolensin 77.899 [M − H] − 256.0736 255.0663 255.0678 5.9 135, 119 BB
58 C15H12O5 3’,4’,7-Trihydroxyisoflavanone 78.287 [M − H] − 272.0685 271.0612 271.0612 0.0 177, 151, 119, 107 * JM, BB
59 C15H10O5 3’-Hydroxydaidzein 81.816 [M + H]+ 270.0528 271.0601 271.0591 −3.7 253, 241, 225 RI
Stilbenes
60 C20H22O8 Resveratrol 5-O-glucoside 38.063 [M − H] − 390.1315 389.1242 389.1245 0.8 227 JM
Other Polyphenols
Curcuminoids
61 C20H18O5 Demethoxycurcumin 81.976 [M − H] − 338.1154 337.1081 337.108 −0.3 217 PT
Furanocoumarins
62 C13H10O5 Isopimpinellin 4.478 [M + H]+ 246.0528 247.0601 247.0605 1.6 232, 217, 205, 203 PT
Hydroxybenzaldehydes
63 C8H8O2 p-Anisaldehyde 30.338 **[M + H]+ 136.0524 137.0597 137.0599 1.5 122, 109 * JM, BB
64 C7H6O2 4-Hydroxybenzaldehyde 44.756 [M − H] − 122.0368 121.0295 121.0298 2.5 77 * JM, PT, BB, RI
Hydroxybenzoketones
65 C9H10O7S 2-Hydroxy-4-methoxyacetophenone 5-sulfate 9.446 [M − H] − 262.0147 261.0074 261.0067 −2.7 181,97 BB
66 C10H12O5 2,3-Dihydroxy-1-guaiacylpropanone 21.442 **[M − H] − 212.0685 211.0612 211.0605 −3.3 167, 123, 105, 93 * RI, JM
Hydroxycoumarins
67 C10H8O4 Scopoletin 43.298 [M − H] − 192.0423 191.035 191.0361 5.8 176 JM
Other Polyphenols
68 C12H16O7 Arbutin 5.129 [M − H] − 272.0896 271.0823 271.0828 1.8 109 JM
69 C27H22O12 Lithospermic acid 5.834 [M − H] − 538.1111 537.1038 537.1037 −0.2 493, 339, 295 BB
70 C36H30O16 Salvianolic acid B 28.598 [M − H] − 718.1534 717.1461 717.1436 −3.5 519, 339, 321, 295 PT
Phenolic Terpenes
71 C20H28O4 Carnosic acid 80.419 [M − H] − 332.1988 331.1915 331.1905 −3.0 287, 269 PT
Tyrosols
72 C10H12O4 3,4-DHPEA-AC 8.172 [M − H] − 196.0736 195.0663 195.0666 1.5 135 * RI, WN
73 C14H20O8 Hydroxytyrosol 4-O-glucoside 9.777 [M − H] − 316.1158 315.1085 315.1076 −2.9 153, 123 BB

** Compounds were detected in both negative [M − H] − and positive [M+H]+ mode of ionization while only single mode data was presented. Pear samples mentioned in abbreviations are Packham’s Triumph “PT”, Josephine de Malines “JM”, Beurre Bosc “BB’’, Winter Nelis “WN” and Rico “RI”.