Polysaccharides, universal calibration

The difficulties presented by log Kp vs log of standard M are obviated by alternatively plotting log[r ]M vs log wel. For each fraction of a polysaccharide homologous series, log[r ]M vs log we, is superimposable on a so-called universal calibration curve (Grubisic et al., 1967) from which an unknown M2 may be estimated, after substitution in the equation... 

SEC-LS is used to measure molecular weight distribution directly as a polymer elutes from the SEC without universal calibration. For each polymer-solvent system, the specific refractive index increment dn/dc is required, and for most instruments the solvent refractive index is also needed. Table 3 lists selected papers describing SEC-LS measurements of synthetic polymers, copolymers, polysaccharides, cellulosics, and related polymers. 

Universal calibration plot for polyethylene glycol, polyethylene oxide, polysaccharide, and polyacrylamide in 0.10 M sodium nitrate at 35 C. 

Dintzis and Tobin used a porous glass column with a 95% DMSO and 5% HjO mobile phase and found that universal calibration was valid for dextran and amylose (17). Universal calibration was also found to be valid for these two polysaccharides with deactivated silica gel and a pure DMSO system (18). 

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