Electrochemical determination of riboflavine and pyridoxine by using multi-walled carbon nanotube and electrochemically reduced graphene oxide modified glassy carbon electrodes

In this study, the electrochemical determination of B2 vitamin (riboflavin) and B6 vitamin (pyridoxine) was performed by using multi-walled carbon nanotubes (MWCNT) and electrochemically reduced graphene oxide (ERGO) modified glassy carbon electrodes (GCEs). The chronoamperometry method was used to prepare the MWCNT modified electrode (GCE/MWCNT) and the cyclic voltammetry (CV) method was used to prepare the ERGO modified electrode (GCE/ERGO). MWCNT and ERGO modified electrodes were characterized by field emission-scanning electron microscopy (FE-SEM) and Fourier transform infrared spectroscopy (FT-IR) methods. The electrochemical behavior of the modified electrodes was investigated by the CV method in the potassium chloride solution containing the ferro-ferricyanide redox probe. Electrochemical determination of the B2 and B6 vitamins was performed by differential pulse voltammetry (DPV). Linear working range for the B2 vitamin was found to be 4.0×10−3–1.0 µmol L−1 at the GCE/MWCNT electrodeand 0.10–40.0 µmolL−1at theGCE/ERGO electrode. The detection limit for MWCNT and ERGO modified GCEs was determined to be 0.001 µmol L−1 and 0.016 µmol L−1,respectively. Linear working range for the B6 vitamin was found to be 8.0–1000 at the GCE/MWCNT electrode and 20–1000 µmol L−1 at the GCE/ERGO electrode. The detection limit for MWCNT and ERGO modified GCE was determined to be 0.0028 µmol L−1 and 0.014 µmol L−1,respectively. These electrochemical sensors exhibited very high electrocatalytic activity toward the oxidation of B2 and B6 vitamins.