The effect of different GO reduction strategies on the lower level electrochemical determination of Epinephrine and Serotonin in quaternary mixtures

Abstract

The effect of different reduction techniques on the structure and electrochemical sensing properties of reduced graphene oxide (RGO) was systematically studied. The comparison of the electrochemical properties of three RGOs formed by chemical reduction using sodium borohydride, hydrazine monohydrate and hydrothermal reduction was investigated. The electrodes modified with RGOs showed an excellent electrocatalytic effect by enhancing the anodic current and decreasing the electrode potential on the oxidation of epinephrine (EPN), and serotonin (SER). The effect of scan rate, pH, stability and reproducibility of the sensor was thoroughly investigated. Although all the RGOs obtained from different reduction strategies had very similar characteristics, NaBH4 reduced sample had better current response. The anodic peak current showed a linear relation with the EPN and SER concentration in a wide range of 70 nM-0.5 mM, 100 nM-2 mM respectively. The detection limit (LOD) of 0.33 nM and 3.99 nM were obtained for EPN and SER respectively. The modified electrode sensor was very effective for simultaneous determination of EPN, SER, Uric acid (UA) and Acetaminophen (AC) with well separated peaks at −0.069, 0.091, 0.269 and 0.395 V. The peak to peak separation values (ΔEpa) of EPN-AA, SER-EPN, AC-SER and AA-AC were 0.16, 0.178, 0.126, and 0.464 V. This work demonstrates the practical utility of the single component modified electrodes for measurements of EPN, SER in human blood serum and urine.