Binary mobile phases for the analysis of poly(methyl methacrylates) via thin-layer chromatography

Tetrahydrofuran-containing binary mobile phases used for the thin-layer chromatography study of poly(methyl methacrylates) are comprehensively investigated. The peculiarities of the transition from the adsorption regime to the exclusion regime through the conditions critical for PMMA are studied in a wide range of molecular masses at different macromolecule-to-pore size ratios. Binary phase compositions corresponding to the critical conditions are determined, and chromatographic results are compared with viscometry data. In the adsorption region near the critical conditions, the dependence of the retention parameter on the molar fraction of tetrahydrofuran in the mixtures is approximated by a linear function. The slope of this dependence is shown to grow with both the molecular mass of the polymer and the thermodynamic quality of the mixed solvent.