Abstract
Scanning transmission X-ray microscopy and micro carbon X-ray Absorption Near Edge Spectroscopy (C-XANES) can provide quantitative information regarding the distribution of the biopolymers cellulose, hemicellulose, and lignin in vascular plant cell walls. In the case of angiosperms, flowering plants, C-XANES may also be able to distinguish variations in lignin monomer distributions throughout the cell wall. Polysaccharides are susceptible to soft X-ray irradiation induced chemical transformations that may complicate spectral analysis. The stability of a model polysaccharide, cellulose acetate, to variable doses of soft X-rays under conditions optimized for high quality C-XANES spectroscopy was investigated. The primary chemical effect of soft X-ray irradiation on cellulose acetate involves mass loss coincident with de-acetylation. A lesser amount of vinyl ketone formation also occurs. Reduction in irradiation dose via defocusing does enable high quality pristine spectra to be obtained. Radiation induced chemical modification studies of oak cell wall reveals that cellulose and hemicellulose are less labile to chemical modification than cellulose acetate. Strategies for obtaining pristine C-XANES spectra of polysaccharides are presented.
Original language | English (US) |
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Pages (from-to) | 57-64 |
Number of pages | 8 |
Journal | Journal of Electron Spectroscopy and Related Phenomena |
Volume | 170 |
Issue number | 1-3 |
DOIs | |
State | Published - Mar 2009 |
Funding
GDC and JB thank the NSF Ocean Sciences program (OCE-0221336) and NASA's Astrobiology Program (NAI) for helping to support this research. The National Synchrotron Light Source is a DOE supported facility.
Keywords
- Carbon XANES
- Cellulose acetate
- Polysaccaride
- Radiation damage
- Scanning transmission X-ray microscopy
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Radiation
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics
- Spectroscopy
- Physical and Theoretical Chemistry