LAUSR

Abstract In the paper, water-dispersed graphene-GQDs composites were prepared by electrochemical exfoliation under alternating voltage combining ultrasonic treatment. The effects of alternating voltage, alternating frequency and the distance between electrodes were carefully explored. The results showed that the quality of composites prepared by alternating voltage was higher than that by direct voltage. The existence of graphene quantum dots (GQDs) hindered the agglomeration of graphene and facilitated dispersion of graphene in water. The sensor based on the obtained graphene-GQDs composites was used to detect dopamine (DA). The electrochemical investigation showed that the sensor had good selectivity and wide linear ranges for the detection of DA (0.1–100 µM). The detection limit could be down to 3 × 10−8 M (S/N = 3) with a sensitivity of 14.25 µA µM−1 cm−2.