USING CAPILLARY ELECTROPHORESIS FOR THE CHARACTERIZATION OF A WATER-SOLUBLE POLYAMPHOLYTE

LAURA ANDREA DEL RIO; L. V. LOMBARDO LUPANO; J. M. LÁZARO MARTÍNEZ; CAMPODALL' ORTO, V.; NORA M. VIZIOLI

Lima

Simposio; LACE 2013: 19th Latin-American Symposium on Biotechnology, Biomedical, Biopharmaceutical and Industrial Applications of Capillary Electrophoresis and Microchip Technology; 2013

LatinCE

Polyampholytes are polymers containing both cationic and anionic repeat groups. The competition between the acid-base equilibria of these groups leads to physical properties with many applications, mostly related to modifying flow and stability properties of aqueous solutions and gels. For example, they can be used to destabilize a colloidal suspension and to initiate flocculation. They can also be used to provide surface charges to neutral particles, enabling them to be dispersed in aqueous solution. Polyampholytes are thus often used as thickeners, emulsifiers, conditioners, and clarifying agents. They are used in water treatment and for oil recovery. Many soaps, shampoos, cosmetics, and even foods incorporate polyampholytes. In the present study, a water soluble polyampholyte was synthesized from ethyleneglycol diglycidyl ether (EGDE), methacrylic acid (MAA) and imidazole (IM), according to a two-steps strategy. First, a mixture of EGDE and IM was incubated at 50°C for 24 h, and then, MAA was incorporated and maintained at 60°C for additional 24 h. Last, benzoyl peroxide was added to obtain an elastic and water soluble solid polymer. The synthesis process was monitored by ATR-FTIR: disappearance of IR absorption bands corresponding to epoxy and vinyl groups was verified. Typical IR bands from carboxyl, alcohol and IM groups were also observed. The synthesized material presents statistical alternating monomers, including a high number of possible monomer combinations. Cleaning of the material was performed by dialysis through a membrane provided with a 12 kDa molecular mass cutoff. Samples of polyampholyte were analyzed by capillary electrophoresis. The background electrolyte consisted of a 50 mM sodium phosphate solution, adjusted at pH 4.0, 5.0, 6.0, 7.0, and 8.0. At pH lower or equal to 7.0, all polymer fractions were positively charged and migrated faster than the electroosmotic flow marker, while at pH 8.0 they were negatively charged. Samples of polyampholytes from different batches showed the same pH-dependent electrophoretic profile. Washing solutions from the dialysis step presented very few components, which were base-line resolved when analyzed by capillary electrophoresis.