NONEXCLUSION EFFECTS IN AQUEOUS SEC - BEHAVIOR OF SOME POLYELECTROLYTES USING ONLINE MASS DETECTORS

Aqueous Size Exclusion Chromatography (SEC), coupled with both a homem ade viscometer and a low angle laser light scattering detector (LALLS) is a very valuable analytical tool for the characterization of polyel ectrolytes. The great interest of this dual mass detection is that mol ecular weights can be calculated by two different and independent ways . When comparing the two sets of results, it is possible to check whet her every chromatographic parameters has been optimized or non exclusi on effects occur in addition to the size exclusion mechanism. Two sets of polyelectrolytes were used in this study : a set of sodium polysty rene sulfonate (NaPSS) standards, as anionic polymers and a family of copolymers of acrylamide and N,N,N-trimethylaminoethyl chloride acryla te (AM/CMA) synthetized in our Laboratory as cationic polymers. Import ant non-exclusion effects, repulsion and adsorption have been encounte red in their study. The results are discussed as a function of the ion ic strength of the mobile phase and the nature of the salt that was ad ded and interpreted through polymer-packing interactions. The strong i nfluence of the nature of the column, and especially their history is described.