Voltammetric determination of vitamin B2 by using a highly porous carbon electrode modified with palladium-copper nanoparticles

Palladium-copper nanoparticles were placed on activated carbon to give a nanocomposite for electrochemical sensing of riboflavin (vitamin B-2). The activated carbon was produced by pyrolysis of natural waste of pistachio nutshells after KOH activation and under a nitrogen atmosphere. The carbons possess a large surface area and micro/meso-porosity. The nanocomposite was characterized by a variety of techniques to confirm structures and morphology. A screen-printed electrode modified with the composite was examined by EIS, CV, DPV, and amperometry. The effects of pH value, scan rate, and stability of the modified electrode were studied. Under optimized conditions, vitamin B-2 displays a well-expressed oxidation peak at -0.15V (vs. Ag/AgCl) in solutions with a pH value of 7.0. The voltammetric signal increases linearly in the 0.02 to 9M concentrations range and a lower detection limit of 7.6 pM. The sensor was successfully applied to the determination of vitamin B-2 even in the presence of other common vitamins and in (spiked) raw milk samples.