Determination of ultrahigh molar mass of polyelectrolytes by Taylor dispersion analysis

• Published in: Journal of Chromatography A Vol. 1670; pp. 462949 - 7
• Main Authors: Leclercq, Xiaoling, Leclercq, Laurent, Guillard, Alexis, Rodriguez, Laurent, Braun, Olivier, Favero, Cédrick, Cottet, Hervé
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 10-05-2022; Elsevier
• Subjects: Anions; Chemical Sciences; Electrophoresis, Capillary - methods; Molecular Weight; Polyacrylamides; Polyelectrolytes; Polymers; Polymers - chemistry; Silicon Dioxide; Size-based separations; Taylor dispersion analysis; Ultrahigh molar mass determination; Taylor dispersion analysis; Size-based separations; Polyacrylamides; Ultrahigh molar mass determination; polyacrylamides; size-based separations; ultrahigh molar mass determination
• ISSN: 0021-9673; 1873-3778
• DOI: 10.1016/j.chroma.2022.462949

•Analysis of ultrahigh molar mass polyacrylamides up to 25×106 g/mol by TDA.•Linear logRh vs logMw correlation obtained by TDA on a broad range of molar masses.•TDA results were consistent with those obtained by static light scattering.•TDA is a straightforward, absolute and rapid method for size-based characterization.
Taylor dispersion analysis (TDA) was successfully applied to obtain broadly distributed, ultrahigh molar masses of industrial anionic polyacrylamides (IPAMs) up to 25 × 106 g/mol, far beyond the limits of Size Exclusion Chromatography (SEC) (about 7.3 × 106 g/mol for anionic polyacrylamides standards (APAM)). Two protocols of TDA differing in capillary surface and rinsing procedure were employed: (i) bare fused silica capillaries under intensive between-run rinsing with 1 M NaOH, and (ii) fused silica capillaries coated with polyelectrolyte multilayers composed of polydiallyldimethylammonium chloride polycation and sodium polystyrenesulfonate polyanion under simple rinsing with background electrolyte. Both cases led to similar results and in agreement with those obtained by static light scattering, the rinsing capillary step being much shorter in the second case (8 min instead of 30 min). The data processing of the obtained taylorgrams was realized using multiple-Gaussian fitting of the overall taylorgrams, by separating the contribution of low molar mass impurities from the polymeric profiles, and by determining the mean hydrodynamic radii and diffusion coefficients of the polymers. The molar masses of ultra-high molar mass industrial anionic polyacrylamides (IPAM) were derived from the hydrodynamic radii according to logRh versus logMw linear correlation established with APAM standards. Compared to capillary gel electrophoresis for which the size separation was only feasible up to Mw ∼ 10×106 g/mol due to field induced polymer aggregation, TDA largely extended the range of accessible molar mass with easy-to-run and time saving assays.