Determination of Riboflavin by Nanocomposite Modified Carbon Paste Electrode in Biological Fluids Using Fast Fourier Transform Square Wave Voltammetry

Herein, fast Fourier transformation square-wave voltammetry (FFT-SWV) as a novel electrochemical determination technique was used to investigate the electrochemical behavior and determination of Riboflavin at the surface of a nanocomposite modified carbon paste electrode. The carbon paste electrode was modified by nanocomposite containing Samarium oxide (Sm۲O۳)/reduced graphene oxide (RGO) (۲:۱) to improve detection sensitivity of Riboflavin under optimal experimental conditions. Furthermore, the signal-to-noise ratio was significantly increased by application of discrete fast Fourier transformation analysis, background subtraction and two-dimensional integration of the electrode response over the selected potential range and the time window. Obtained cyclic voltammograms demonstrated a diffusion-controlled reversible electron transfer reaction for Riboflavin in phosphate buffer solution (pH=۷.۲). The peak potential values were pH-dependent, involving the same numbers of protons and electrons. To obtain the maximum sensitivity, some effective parameters such as scan rate (۱۰ mV/s), accumulation time (۰.۲ s) and potential (+۴۰۰ mV), frequency (۱۴۲۰ Hz) and amplitude (۲۰ mV) were optimized. As a result, determination of Riboflavin using FFT-SWV showed a linear range of response from ۱۰ to ۴۰۰ nM (R۲=۰.۹۹۹۳), with limit of detection of ۰.۸۶ nM. An acceptable recovery percent was also obtained for Riboflavin in human plasma samples as criteria of measurement applicability of the proposed modified electrode.

Keywords:

fast Fourier transforms square wave voltammetry , Riboflavin , Reduced graphene Oxide , Samarium Oxide