Electrochemiluminescence sensor for hexavalent chromium based on the graphene quantum dots/peroxodisulfate system

A electrochemiluminescent (ECL) sensor has been designed to detect hexavalent chromium (Cr(VI)) in environmental water samples based on the fact that Cr(VI) can collisionally quench the ECL signal of graphene quantum dots/peroxodisulfate (GQD/S2O82−) system. After optimizing some important experimental conditions including the concentrations of GQDs and S2O82−, response time, and pH value of solution, the ECL sensor has been finally developed. The ECL sensor exhibits a wide linear response range (50 nM-60 μM), excellent selectivity, and high sensitivity (detection limit of 20 nM, S/N = 3). Furthermore, the developed sensor has been applied in the detection of Cr(VI) in a spiked river water. The result suggests that the sensor can offer a simple, green, low cost, high selectivity and sensitivity detection of Cr(VI).