Quantitative determination of the average molecular weights of dextrans by diffusion ordered NMR spectroscopy

Diffusion ordered NMR (DOSY) was applied to the determination of the average molecular weights of polymers based on the dependence of the measured self-diffusion coefficient D on the corresponding weights of a number of polymers of the same type. As a rule, a calibration function is plotted by varying DOSY experimental parameters for each particular test sample; however, this approach is inapplicable to the development of a standard procedure for the quantitative assessment of the molecular weights of dextrans. In this article, an optimization method is considered to ensure high resolution in terms of the values of D for dextrans without varying experimental conditions; this method makes it possible to evaluate the average molecular weights of dextrans with a high accuracy over a wide range of their values.