13C CP/MAS NMR spectra of pectins: a peak-fitting analysis in the C-6 region

Abstract

13C CP/MAS NMR spectra of pectin samples were measured and interpreted. The influence of methylesterification and O-acetylation on chemical shifts of pectin carbons was studied using model pectate, pectinates, and their acetylated derivatives. The spectra were analysed also by peak fitting in C-6 region to obtain the values of methylation (DM), amidation (DAm) and acetylation (DAc), degrees. The results were in a good agreement with both convenient methods (photometry, elemental analysis) and the NMR method based on the relative areas of OCH3 (DM) and CH3 (DAc) resonances.

Keywords

• 13c cp/mas nmr
• pectins
• peak fitting
• degrees of methylation (dm)
• degrees of acetylation (dac)