Construction and application of electrochemical sensors for the detection of naphthol

Abstract

A poly(L-cysteine)/graphene oxide composite modified glassy carbon naphthol electrode is constructed, which is used for simultaneous determination of 1-naphthol (1-NAP) and 2-naphthol (2-NAP). The electrochemical behavior of 1-NAP and 2-NAP on the modified electrode are investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV), and the conditions to modify the electrode and to detect naphthol isomers are optimized. The results show that the modified electrode has an excellent electrocatalytic activity in the oxidation of the naphthol in phosphate buffered solution of 0.1 mol/L PBS (pH 7.5). The difference of oxidation peak potential between 1-naphthol and 2-naphthol could reach 0182 V, which is almost large enough to achieve the simultaneous detection for 1-naphthol and 2-naphthol in a mixture solution. Under optimized experimental conditions, differential pulse voltammetry is adopted to detect naphthol isomer. It is found that the oxidation peak currents of 1-NAP and 2-NAP show a good linear relationship with the concentration in the range of 2~40 μmol/L and 1~40 μmol/L, respectively. The detection limits (S/N=3) for 1-NAP and 2-NAP are 0.19 μmol/L and 0.12 μmol/L, respectively. The modified electrode shows good stability and reproducibility and has strong anti-interference ability in the detection. The electrode is applied to determine 1-NAP and 2-NAP in real water samples, and the average recoveries are in the range of 98.9% to 101.7% and 97.7% to 102.1%, respectively.

Keywords

• electroanalytical chemistry
• naphthol
• electrochemical sensor
• poly(L-cysteine)
• graphene oxide