Amperometric Titration of Fructan Oligosaccharides of Agave Tequilana Webber, Blue Variety, in a Rotating Disk Electrode

This paper deals with a simple, rapid and sensitive method for quantifying oligosaccharides of fructans of Agave Tequilana Webber a Blue Variety. The method is based on the oxidation of the carbonyl group of the oligosaccharide in its linear open-ring with ferricyanide ions in a RDE (rotating disk electrode). The amperometric titration is carried out at different temperatures, e.g., 60, 65, 70, 75, 80 and 85 degrees C as a strategy to control the amount of oligosaccharides with the open-ring as a function of their molecular size. The proposed method allows us to determine concentrations of oligosaccharides as low as 0.71 mM. A calibration curve between the limiting current of the Fe(CN)(6)(3-)/Fe(CN)(6)(4-) pair and the concentration of the oligosaccharides taking into account the effect of temperature in the physical properties of the system, such as, density, diffusion coefficients and viscosity is also presented.