Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was employed to analyse cellulose viscose fibres treated with different chitosan-based solutions. The analysis reports several new features in the TOF-SIMS spectra for systems with various forms of chitosan-treated surfaces. The characteristic positive ion TOF-SIMS signals for chitosan are reported at m/z 147.90, 207.07, and 221.09, and characteristic signals for trimethyl chitosan are present at m/z 58.03 and 102.09. Furthermore, new fragments were suggested to characterise acetylated chitosan molecules. The relative surface concentrations of different species were obtained based on the specific signal ratios (originating from a specific fragment and cellulose). SIMS imaging was then performed in order to investigate the surface distribution of chitosan, trimethyl chitosan, and Na-containing nanoparticles. In order to perform TOF-SIMS imaging, the above-mentioned characteristic signals were employed and m/z 22.99 was used for Na nanoparticles.

Matjaž Finšgar, Tijana Ristić, Pedro Fardim, Lidija Fras Zemljič, Time-of-flight secondary ion mass spectrometry analysis of chitosan-treated viscose fibres, Analytical Biochemistry, Volume 557, 2018, Pages 131-141, ISSN 0003-2697, https://doi.org/10.1016/j.ab.2018.07.021.
(http://www.sciencedirect.com/science/article/pii/S0003269718304895)