Electrochemical sensor based on bismuth-film electrode for voltammetric studies on vitamin B2 (riboflavin)

Abstract

Riboflavin (or vitamin B2) was successfully studied by voltammetric techniques and determined in oral, syrup and tablet samples using an ex situ plated bismuth-film electrode (BiFE). Cyclic voltammetry demonstrated that in acetate buffer (pH 4.0) vitamin B2 undergoes an adsorption-controlled quasi-reversible electron transfer reaction. The peak potentials observed were pH-dependent, involving the same numbers of protons and electrons. The calibration curve provided by square-wave adsorptive stripping voltammetry (SWAdSV) exhibited two slopes: the first ranged from 0.3 to 0.8μmolL−1 vitamin B2 and the second from 1.0 to 9.0μmolL−1. In the case of the first slope, the detection limit was 100nmolL−1 and the quantification limit was 300nmolL−1. Also, for the measurements, excellent selectivity, repeatability and stability were attained. Fluorescence was employed as the comparative technique and the outstanding performance of the BiFE-SWAdSV for riboflavin determination was verified.