Light-induced yellowing of selectively 13C-enriched dehydrogenation polymers (DHPs). Part 1, Side-chain 13C-enriched DHP ([alpha], [beta], and [gamma]-13C)

Abstract

Light-induced yellowing has been studied using side-chain ([alpha], [beta], and [gamma]) 13C-enriched DHP (dehydrogenation polymer) and quantitative solution state 13C NMR spectroscopy. The DHP was formed from 13C-enriched coniferin using an enzymatic system consisting of [beta]-glucosidase, glucose oxidase, and peroxidase in a pH 6 buffer solution. The DHP was applied to filter paper, irradiated with UV/VIS light and the photodegraded DHP was extracted and analyzed. The NMR study revealed a drastic decrease in the amount of coniferyl alcohol end groups with the formation of end groups of the vanillin type and small amounts of end groups of the vanillic acid type. The results indicated a moderate formation of [alpha]-carbonyls, however, no significant decrease in the amount of [beta]-O-4 structures in the extractable part of the irradiated DHP could be established, based on difference spectra corresponding to the 13C-enriched DHP.

Citation

Parkas, Jim; Paulsson, Magnus; Terashima Noritsugu; Westermark, Ulla; Ralph, Sally. 2004. Light-induced yellowing of selectively 13C-enriched dehydrogenation polymers (DHPs). Part 1, Side-chain 13C-enriched DHP ([alpha], [beta], and [gamma]-13C). Nordic pulp and paper research journal. Vol. 19, no. 1 (2004): Pages 29-36