Time-of-Flight Secondary Ion Mass Spectrometry Analysis of Polyethylene Glycol Penetration into Wood Cell Walls
D Jeremic, P Cooper, P Brodersen
Penetration of high molecular weight polyethylene glycol (PEG) into wood cell walls was investigated in red pine. PEG of different molecular weights (1000, 8000 and 20000) was labelled by bromination and treated samples were analyzed on Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) in dynamic mode. Both negative and positive spectra of the samples were collected in high spatial (bunched), high spectral (burst), and an intermediate (burst alignment) resolution mode. Spectral and image data were statistically analysed by principal component analysis (PCA). Negative spectra distinguished untreated from treated samples, showing Br allocation in cell walls of all treated samples. Positive spectra did not provide differentiation between PEG and wood components. Penetration of PEG of all molecular weights into cell walls was confirmed even in case of treatments with PEG 20000.