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 (sm2o3)/reduced graphene oxide (rgo) (2:1) 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=7.2). 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 (10 mv/s), accumulation time (0.2 s) and potential (+400 mv), frequency (1420 hz) and amplitude (20 mv) were optimized. as a result, determination of riboflavin using fft-swv showed a linear range of response from 10 to 400 nm (r2=0.9993), with limit of detection of 0.86 nm. an acceptable recovery percent was also obtained for riboflavin in human plasma samples as criteria of measurement applicability of the proposed modified electrode.