Taylor Dispersion Analysis of Polysaccharides Using Backscattering Interferometry

• Published in: Analytical chemistry (Washington) Vol. 89; no. 12; pp. 6710 - 6718
• Main Authors: Saetear, Phoonthawee, Chamieh, Joseph, Kammer, Michael N, Manuel, Thomas J, Biron, Jean-Philippe, Bornhop, Darryl J, Cottet, Hervé
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 20-06-2017
• Subjects: Absorption; Analytical chemistry; Assembly; Backscattering; Capillary electrophoresis; Capillary flow; Chemical Sciences; Chemistry; Diffusion coefficient; Dispersion; Electrophoresis; Fluid mechanics; Fused silica; Interferometry; Laminar flow; Molecular diffusion; Polymers; Polysaccharides; Refractivity; Saccharides; Silica; Silicon dioxide; Ultraviolet radiation
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/acs.analchem.7b00946

Taylor dispersion analysis (TDA) allows the determination of the molecular diffusion coefficient (D) or the hydrodynamic radius (R h) of a solute from the peak broadening of a plug of solute in a laminar Poiseuille flow. The main limitation plaguing the broader applicability of TDA is the lack of a sensitive detection modality. UV absorption is typically used with TDA but is only suitable for UV-absorbing or derivatized compounds. In this work, we present a development of the TDA method for non-UV absorbing compounds by using a universal detector based on refractive index (RI) sensing with backscattering interferometry (BSI). BSI was interfaced to a capillary electrophoresis-UV instrument using a polyimide coated fused silica capillary and an in-house designed flow-cell assembly. Polysaccharides were selected to demonstrate the application of TDA-BSI for size characterization. Under the conditions of validity of TDA, D and R h average values and the entire R h distributions were obtained from the (poly)­saccharide taylorgrams, including non-UV absorbing polymers.