Simultaneous Detection of Naphthol Isomers with a 3D-Graphene-Nanostructure-Based Electrochemical Microsensor

Naphthol is a widely used chemical and medical detection biomarker, but it is harmful to human health and the environment. Therefore, a highly sensitive detection method for naphthol is urgently required. Herein, an electrochemical microsensor for the simultaneous detection of naphthol isomers was fabricated by the in situ growth of a three-dimensional graphene network (3DGN) on screen-printed electrodes. The microsensor exhibited good electrochemical sensing responses to typical isomers of naphthol (1-NAP and 2-NAP). Using the differential pulse voltammetry (DPV) method, the microsensor successfully realized the electrochemical detection of 1-NAP, 2-NAP, and naphthol isomer mixtures. Whether detecting naphthol isomers individually or simultaneously, the microsensor exhibited a good linear relationship for 1-NAP and 2-NAP in a wide range of concentrations. For the simultaneous detection of naphthol isomers, the limit of detection (LOD) of the microsensor to 1-NAP reached 10 nM, and the LOD for 2-NAP was about 20 nM. The microsensor also showed good selectivity, reproducibility, and stability. The simultaneous quantitative detection of 1-NAP and 2-NAP was also successfully achieved in synthetic urine samples.