%0 Journal Article
%T Characterization of Native and Modified Starches by Potentiometric Titration
%A Diana Soto
%A Jose Urdaneta
%A Kelly Pernia
%J Journal of Applied Chemistry
%D 2014
%R 10.1155/2014/162480
%X The use of potentiometric titration for the analysis and characterization of native and modified starches is highlighted. The polyelectrolytic behavior of oxidized starches (thermal and thermal-chemical oxidation), a graft copolymer of itaconic acid (IA) onto starch, and starch esters (mono- and diester itaconate) was compared with the behavior of native starch, the homopolymer, and the acid employed as a graft monomer and substituent. Starch esters showed higher percentages of acidity, followed by graft copolymer of itaconic acid and finally oxidized starches. Analytical techniques and synthesis of modified starches were also described. 1. Introduction Titration is an analytical technique commonly used in many research and industrial chemistry applications. This involves the measured addition of a solution of known concentration of chemical (titrant) to determine the concentration of another chemical (analyte) in a second solution. The chemical in the titrant reacts in a known manner with the analyte material. When the reaction of these chemicals/materials is complete, a surplus of the titrant is detected as a specific end point marking the end of titration. The end point can be determined by several methods: indicators of pH, redox indicators, potentiometry, conductometry, isothermal calorimetry, spectrophotometry, and amperometry [1]. Analytical techniques for this research included potentiometric titration. Potentiometric titration, based on the measurement of pH changes, is a versatile technique with a wide range of applications. It is a well-established analytical method always effective for simple acid-base systems [2, 3]. For over 70 years it has been applied to study macromolecules, whose early use was limited to the analysis of the behavior of proteins. At that time, the application for studying acid synthetic polymers was applied almost exclusively to poly(acrylic acid) and poly(methacrylic acid) [4]. Nowadays it is still used to investigate the dissociation behavior of poly(acrylic acid) [5] but has expanded to study poly(itaconic acid) [6, 7], copolymers of maleic acid with various olefins [5], styrene [8], and ionization amphiphilic diblock and triblock copolymers [9]. In this study the use of potentiometric titration for the characterization of native and modified starches technique is highlighted. The soluble natural polymers include polynucleotides, polypeptides, and polysaccharides such as starch, cellulose, and chitosan. Due to increased interest in the use of polysaccharides for a wide range of practical applications, potentiometric
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