Apparent molecular weight, concentration

To overcome the problem of non-ideality the work be carried out at the Q temperature because in nonideal solutions the apparent Molecular weight is a linear function of concentration at temperatures near Q and the slope depending primarily on the second virial coefficient. 

Above a certain concentration, the turbidity of sodium dodecyl sulfate (molecular weight = 288) solutions increases with concentration as if particles in the colloidal size range were present. Use the following dataf to evaluate the apparent molecular weight of the species responsible for the scattering. For this system H = 3.99 x 10 6. 

The variation of the apparent molecular weight with concentration was thus ascertained. The results were expressed in terms of the association factor... 

Fig. 6. Concentration dependences of a apparent molecular weights ", and b freezing-point depression 6 per unit concentration c in benzene of poly(a-phenylethyl isocyanide) of Mn = 34800. [Reproduced from Ref. (21), with permission of J. Wiley and Sons, Publ.]...

At pH 2.5 on the positive side of the isoelectric point, strong association is observed. At concentrations as low as 5 x 10"5 g/ml, the apparent molecular weight did not decrease below that of the dimer (Schmidt 1970C). 

Here we present typical examples of systems on which such measurements have been carried out, and we show the magnitude of the contribution of such interactions to apparent molecular weights obtained if the proper correction is not made. The systems examined are / -lactoglobulin in water-2-chloroethanol medium and DNA in high salt concentration. 

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