Submitted to: Journal of Wood Chemistry and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/7/2006
Publication Date: 5/12/2006
Citation: Holtman, K.M., Jameel, H., Chang, H., Kadla, J.F. 2006. Quantitative 13c nmr characterization of milled wood lignins isolated by different milling techniques. Journal of Wood Chemistry and Technology, 26(1): 21-34.
Interpretive Summary: NMR is a powerful tool for characterization of plant materials and the ability of researchers to obtain more, quantitative data is increasing with advances in spectrometric techniques. This paper shows an example of how solution-state 13C NMR can be utilized to assess differences in the biomass fractions isolated from the same source but by different techniques. This study shows that there can be a significant impact of the isolation technique on the lignin structure. The ultimate goal of this work is to advance knowledge of NMR spectroscopy of plants and ultimately to drive towards analysis of lignin in intact wood samples.
Technical Abstract: MWL preparations prepared from finely milled wood flour produced by different milling techniques were compared by quantitative 13C NMR. Wiley wood meal was milled for either six weeks in a porcelain rotary mill with porcelain balls, or by two variations of our standard technique. Specifically the Wiley wood meal was milled for one week in the rotary mill followed by 48 hours of vibratory ball-milling with steel balls either in toluene or under a N2 atmosphere. Results showed that the vibratory-milled samples were similar in structure with the exception that the preparation milled under N2 had higher aliphatic and phenolic hydroxyl contents. The rotary-milled sample on the other hand had a much lower '-O-4’ and hydroxyl content along with a higher degree of condensation and oxidized side chain structures.