Expanding the Library of Secondary Ions That Distinguish Lignin and Polysaccharides in Time-of-Flight Secondary Ion Mass Spectrometry Analysis of Wood

Abstract

Extracted pine (Pinus spp.) wood and the holocellulose and cellulose fractions of pine were analyzed by time-of-flight secondary ion mass spectrometry (ToF-SIMS). The main sources of variation among wood constituents were elucidated by principal component analysis (PCA). Peaks characteristic of lignin or polysaccharides were identified through the combination of high mass resolution analyses of pine fractions and high lateral resolution image analyses distinguishing the lignin-rich middle lamella from the secondary cell wall layers in solid wood cross-sections. A collection of peaks was compiled which (1) extends the library of characteristic lignin and polysaccharide secondary ions in wood, (2) can be applied to both high and nominal mass resolution spectra, and (3) is free from peaks that contraindicate between wood components. The removal of additional peaks to avoid mass interferences with common contaminants was also successful. Many of the characteristic peaks were high-intensity fingerprint ions below m/z 100, which provided for rapid analysis of the lignin and polysaccharide biopolymers in woody samples. The analysis also identified important mass interferences with previously reported wood ions.

Recent innovations in analytical methods for the qualitative and quantitative assessment of lignin

“…Mass spectrometry, in its numerous configurations, has been employed to characterize the structure of lignin [62,[67][68][69][70][71][72][73][74][75][76][77]. Time-offlight (ToF) secondary ion mass spectrometry (SIMS) is one such MS design that provides enhanced sensitivity to surface measurements of solid analytes with high mass spectral and spatial resolution, requires limited sample preparation, and yields rapid analyses over wide mass ranges [69][70][71][72]74,76].…”

“…Time-offlight (ToF) secondary ion mass spectrometry (SIMS) is one such MS design that provides enhanced sensitivity to surface measurements of solid analytes with high mass spectral and spatial resolution, requires limited sample preparation, and yields rapid analyses over wide mass ranges [69][70][71][72]74,76]. Goacher et al developed an improved library of secondary ions for the differentiation between lignin and polysaccharide mass fragments [69]. PCA allowed the segregation of mass spectral data as either lignin or polysaccharide peaks from pine.…”

Lignification of ray parenchyma cells in the xylem of Pinus densiflora. Part I: Microscopic investigation by POM, UV microscopy, and TOF-SIMS

“…In other words, the relative intensity of guaiacyl-lignin (G-lignin) was calculated by division of the G-lignin ion counts by the cellulose ion counts. The mass-to-charge ratios (m/z) 137 (C 8 H 9 O 2 + ) and 151 (C 8 H 7 O 3 + and C 9 H 11 O 2 + ) are typical for G-lignins (Saito et al 2005) and those at m/z 127 (C 6 H 7 O 3 + ) and 145 (C 6 H 9 O 4 + ) are for cellulose (Goacher et al 2011). Three replications were performed for each sW, TZ, and hW sample and the average values are presented for the G-lignin concentration in Tr axial and P ray -rich regions in Figure 6.…”

Plasticity, elasticity, and adhesion energy of plant cell walls: nanometrology of lignin loss using atomic force microscopy

“…3) were determined. The fragmentation ions of the major components of biomass are cellulose, guaiacyl (G) lignin, and syringyl (S) lignin 20, 21 . Cellulose units are C 6 H 7 and C 6 H 9 with mass-to-charge ratios m / z  = 127 and 145, respectively.…”