J. A. M. Smit

Size-exclusion chromatography-multiangle laser light scattering analysis of β-lactoglobulin and bovine serum albumin in aqueous solution with added salt

The solution characteristics of beta-LGB (beta-lactoglobulin) and BSA (bovine serum albumin) are reported as determined by size-exclusion chromatography with on-line multiangle laser light scattering, differential refractive index and UV detection. The order of the three in series placed detectors as well as the interdetector volumes have been carefully pointed out. At concentrations below 2.5 mg/ml and at different values of pH the weight-average molecular mass of both proteins have been obtained. They indicate the appearance of monomers, dimers and higher order multimers. For beta-LGB the growth of self-associates could be observed at the isoelectric point over a period of days. The range of applicability of the method is discussed.

The second virial coefficient of polydisperse polymer samples in a good solvent

SummaryIn this paper we present analytical expressions for the osmotic and light-scattering second virial coefficients of polydisperse polymer samples in a good solvent. They are derived using the Schulz and the Lognormal molecular weight distribution respectively. The effect of interpenetrating coils is taken into account. Comparison is made with expressions already derived by Casassa using a hard sphere model. The reduction of the obtained expressions to simple scaling laws is discussed.

An analytical correction for peak broadening in gel permeation chromatography with a molecular weight detector

SummaryIn this paper we present a general expression describing the peak broadening effect on molecular weight averages measured during the elution of a polymer in GPC. This expression is valid for nonlinear column calibration and nonuniform Gaussian spreading across the chromatogram. Comparison is made with analytical relationships derived by Yau, Marais, Hamielec and Netopilik. The methodology developed as an extension of the Pierce and Armonas method is applied to a model system and to elution data of dextrans.