SEC gradients: An alternative approach to polymer gradient chromatography

The development of a chromatographic method capable to separate poly(methyl methacrylate-stat-methacrylic acid) samples with methacrylic acid contents of up to 50% by chemical composition is described. For this purpose a gradient ranging from chloroform to dimethylacetamide on a PSS PROTEEMA column was applied. The application of a conventional gradient resulted in severe breakthrough peaks. Therefore, the recently developed concept of SEC gradients was used. No breakthrough peaks were observed, and the peaks corresponding to samples of different content of methacrylic acid were well resolved. A nearly linear relationship between elution volume and methacrylic acid content was observed. The developed method allows determination of the chemical composition distribution of the above-mentioned class of polymers.