DETERMINATION OF THE DEGREE OF CATIONICITY IN CATIONIC STARCHES BY SOLID-STATE C-13 NMR-SPECTROSCOPY

C-13 solid-state NMR is presented as a rapid and accurate method for determining the degree of substitution in cationic starches. Data are presented for four cationic starches where the cationizing agent is a trimethyl-substituted quarternary amine. Using a rigorous quantitative approach, NMR determined DS values can be obtained that fall within +/-0.01 DS units of those obtained by traditional wet chemical methods. By employing average relaxation parameters, the analysis time can be reduced to roughly one hour at the expense of an increase in uncertainty to only +/-0.03 DS units.