Sensitive voltammetric determination of riboflavin in pharmaceutical and biological samples using FSN-Zonyl-Nafion modified carbon paste electrode

An anti-fouling bipolymeric membrane was used to modify a carbon nanoparticle paste electrode for the determination of riboflavin in real samples. This bipolymeric membrane was constructed from two polymers: perfluorate resin Nafion and fluorosurfactant Zonyl-FSN. Nafion membrane was used as an anti-fouling material and the Zonyl-FSN membrane was used for the enhancement of the electrocatalytic activity towards the electrooxidation of riboflavin. The developed method exhibited a good sensitivity for the determination of riboflavin, in real samples, without any preconcentration step. The fouling effect was controlled by the Nafion membrane that possesses the ability to block the anionic and neutral species to reach on the carbon matrix surface. The proposed FSN/Nafion/CNP electrode was used in a wide concentration range with two linear ranges (1.00x10(-10) - 1.00x10(-7) mol L-1 and 1.00x10(-7) - 1.00x10(-4) mol L-1, respectively) and very low limit of detection (3.03x10(-11) mol L-1). The analytical applicability of the proposed method was demonstrated by performing quantitative measurements of riboflavin from real samples, such as pharmaceutical samples and urine samples with a RSD value lower that 2.75%.