Online Determination of Structural Properties and Observation of Deviations from Power Law Behavior

Synthetic amyloses, pullulans, phytoglycogen, rabbit liver glycogen, oyster glycogen, and dextrans were studied using high-performance size-exclusion chromatography combined with multiangle laser light scattering (MALLS) and online quasi-elastic light scattering (QELS), which provided the RH distributions up to 65 nm. Different structural parameters were extracted from entire molar mass distributions, including the slope of the log-log plot of R H(i) versus M(i)and the rho(i )= R(Gi)/R(Hi)ratio. This approach enabled to observe deviations from the De Gennes scaling law concept. Evidences that the power laws do not obey the general universality were furnished by the observation of strong deviations in the relation between radii and molar masses for the branched polysaccharides, a decrease of rho-parameter with molar mass toward values much lower than theoretically expected, and the fact that relation between rho-parameter and apparent segment density did not show the expected power law decrease with an exponent of 1/3. The universality of scaling behavior seems no longer to be realized if structural heterogeneity governs the system.