A procedure, using combined gel permeation chromatography and low-angle laser light scattering, has been developed for characterizing block copolymers. A compositional heterogeneity parameter, whose variation with molecular weight can be measured, has been defined. The procedure has been applied to copolymers and blends of polystyrene and poly(dimethylsiloxane).

Significant changes in the fractionation of dextran have been observed when conducting semi-continuous gel permeation chromatographic experiments using feeds of different dextran concentration. Using a batch analytical chromatographic apparatus with a column packed with Porasil C and labelled dextrans FITC dextran 20, FITC dextran 40 and FITC dextran 70, concentration and temperature effects on gel permeation chromatography have been determined. Background concentrations of up to 200 g/l and temperatures between 20-80°C were studied.

Two pairs of DuPont Zorbax PSM Bimodal gel permention chromatography columns, packed with porous silica particles have been used fo the fractionation of dextran. High initial efficiencies decreased with use and shrinkage of the bed suggested silica was dissolving. The eluent required a certain ionic strength to prevent some of the dextran being excluded.

A number of rigid column packings (Spherosil-Porasil and DuPont SEC) and semi-rigid packings (two types of Spheron gel and Hydrogel) have been used for the molecular-weight characterisation of dextran by aqueous gel permeation chromatography. Our experience with these packings is reported and the various problems encountered, and their possible causes, are discussed. Our criteria for an acceptable packing have been fractionating range, efficiency, short analysis time and, of particular importance, long-term stability. None of the column packings considered was found to be ideal.

The elution behaviour of ferrocene, ruthenocene and a series of substituted ferrocenes on a gel permeation chromatography support, cross-linked poly- (acryloyl morpholine) (Enzacryl® Gel), has been investigated. For most of the solutes an approximately linear relationship was obtained between logarithm molecular weight and the Wheaton Baumann absolute distribution coefficient (Kd), indicating that the separations were effected via a molecular sieving mechanism.

The synthesis and characterization of a crosslinked poly(acryloyl morpholine) network, Enzacryl® Gel KO, calculated to be effective as a matrix for the g.p.c. of small molecules, is described. Chromatographic performance was evaluated in water, chloroform, dimethylformamide and pyridine. Characteristic g.p.c. behaviour was observed for all standards tested although ‘additional exclusion’ was observed in the case of aliphatic hydrocarbons in the three organic solvents and with aromatic hydrocarbons in chloroform and pyridine. Similar molecular weight fractionation ranges were obtained for poly(ethylene glycols) in the four solvents investigated the molecular weight exclusion limit being less than 1500.

A range of poly(acryloylmorpholine) gel networks have been synthesized by aqueous suspension polymerization of acryloylmorpholine and N,N'-methylene-diacrylamide in differing molar ratios and at different monomer dilutions. Thin-layer techniques and dyed protein standards were employed to evaluate the networks directly as matrices for aqueous gel permeation chromatography. Increase in the Wheaton and Baumann distribution coefficient, Kd, with buffer content of the gel networks was found to hold only when the ratio of acryloylmorpholine to cross-linker was kept constant or was relatively high. Maximum molecular weight exclusion limit (> 2 × 106 for dyed dextran) was observed at high cross-linker concentration.