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

Fragment distribution of thermal decomposition for lignin monomer by QMD calculations using the excited and charged model molecules

“…Fig. 3 shows the calculated distribution of the positive and negative ion charged fragments for the lignin monomer at ground state and including the triplet state with the experimental results in TOF-SIMS [13,14]. In the figure, the calculated positive charge fragment distribution for the lignin monomer including the triplet state is much close to the experimental result, in comparison with the calculated one at …”

“…[12] In the present study, we simulate the thermal decomposition of the lignin monomer including the excited and positive charged model molecules, because Saito et al [13,14] identified a specific fragment (C 6 H 3 (OCH 3 )(OH)CH 2 + at 137 amu) which may correspond to the excited, or charged molecular species.…”

Simulation of SIMS for monomer and dimer of lignin under the assumption of thermal decomposition using QMD method

“…We can conclude the following terms from our simulations of lignin monomer and dimer, in comparison of the experimental values with Saito and co-workers: 20 2)The calculated neutral, positively, and negatively charged fragments were evaluated as (85.0, 6.0, and 9.0%) to the total ones. Thus, QMD simulation enables us to use to analyze polymers in SIMS after a few ten of keV of primary heavy metal ion bombardment, since cleavage of organic bonds for lignin molecules on the outer most surface is considered as examples due to thermal decomposition process.…”

“…By considering the thermal decomposition, we are able to simulate the decomposition of the monomer and dimer of lignin by QMD method in order to compare with experimental results of SIMS. 20,21 As an example of data, Fig. 1 shows the snap shots of the thermal decomposition of the dimer at 0, 2000, and 4000 steps with 0.78 eV energy control using semiempirical AM1 method.…”

Chemical differences between sapwood and heartwood of Chamaecyparis obtusa detected by ToF-SIMS

“…The peak at m/z 137 arises from the C 6 -C 1 benzyl ion ([C 8 H 9 O 2 ] + = 151.0394), and the peak at m/z 151 arise from a double component, the C 6 -C 1 benzoyl ion ([C 8 H 7 O 3 ] + = 151.0394) and the C 6 -C 2 ion ([C 9 H 11 O 2 ] + = 151.0758) [8]. A previous study has shown that the peak at m/z 151 derived from lignin is dominated by the C 6 -C 1 benzoyl ion ([C 8 H 7 O 3 ] + ), not the C 6 -C 2 ion ([C 9 H 11 O 2 ] + ), using synthetic lignin model compound [9]. The relative intensities of the ions derived from lignin in Hinoki cypress showed that lignin was distributed almost uniformly from sapwood to heartwood, in which the intensities of the ion at m/ z 137 were higher than those of the ion at m/z 151 (Fig.…”