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Table 6 LC–MS identification of the main ions detected during oxidation of ferulic acid by PcLac1 and PcLac2

From: Discovery of two novel laccase-like multicopper oxidases from Pleurotus citrinopileatus and their application in phenolic oligomer synthesis

Compound Rt (min) m/z [M-H] MF MS/MS Identification PcLac1 samples PcLac2 samples
Dimers
1 7.07 297.111 C18H17O4 146 (C9H6O2) 109 (C6H5O2) Double-decarboxylated diferulic acid Minor Major
2 7.07 341 C19H17O6 281 (C17H13O4), 267 (C16H11O4), 209 (C14H9O2), 159 (C10H7O2), 146 (C9H6O2) Decarboxylated diferulic acid Major Major
3 7.28 385 C20H17O8 267 (C16H11O4), 239 (C15H11O3) Diferulic acid Major Major
4 7.29 341 C19H17O6 281 (C17H13O4), 267 (C16H11O4), 209 (C14H9O2), 159 (C10H7O2), 146 (C9H6O2) Decarboxylated diferulic acid Major Major
5 7.99 341 C19H17O6 281 (C17H13O4), 267 (C16H11O4), 209 (C14H9O2), 159 (C10H7O2), 146 (C9H6O2) Decarboxylated diferulic acid Major Major
Trimers
6 7.40 577 C30H25O12 193 Triferulic acid Not detected Major
7 7.62 533 C29H26O10 193 Triferulic acid, decarboxylated Not detected Major
8 7.63 577 C30H25O12 193 Triferulic acid Not detected Major
9 7.65 533 C29H26O10 193 (C10H9O4), Triferulic acid, decarboxylated Minor Major
10 7.67 533 C29H26O10 193 Triferulic acid, decarboxylated Not detected Major
11 8.02 533 C29H26O10 193 Triferulic acid, decarboxylated Minor Major
12 8.21 533 C29H26O10 193 Triferulic acid, decarboxylated Minor Major
13 8.35 533 C29H26O10 193 Triferulic acid, decarboxylated Minor Major
14 8.35 565 C30H29O11 193 (C10H9O4), 178 (C9H6O4), 149 (C9H9O2), 134 (C8H6O2) Unknown triferulic acid Major Major
15 8.63 533 C29H26O10 193 Triferulic acid, decarboxylated Not detected Minor
Others
16 7.5 551 C29H28O11 193 (C10H9O4), 178 (C9H6O4), 149 (C9H9O2), 134 (C8H6O2) Triferulic acid, decarboxylated-H2O* Detected Detected
  1. *The MS/MS shows that it is a triferulic acid derivative but it is not obvious how. A carboxyl group and a H2O molecule are missing