A new analysis of the depolymerized fragments of lignin polymer in the plant cell walls using ToF-SIMS

High mass resolution ToF-SIMS spectra by Au+ primary ion bombardment were used to investigate exact structures of characteristic ions of lignin in plant cell walls. Previous study using Ga primary ion bombardment showed the characteristic peaks of guaiacyl lignin at m/z 137 ([C8H9O2]+) and 151 ([C8H7O3]+ and [C9H11O2]+), but it was unclear whether the peak at m/z 151 in the spectrum of lignin in situ in plant cell walls is actually a double-component, [C8H7O3]+ (151.0394) and [C9H11O2]+ (151.0758). This report achieved a higher mass resolution with lignin samples, showing that the peak at m/z 151 is dominated by the C6–C1 benzoyl ion, [C8H7O3]+, not the C6–C2 ion, [C9H11O2]+.