Graphene quantum dots enhanced electrochemiluminescence of cadmium sulfide nanocrystals for ultrasensitive determination of pentachlorophenol

An ultrasensitive electrochemiluminescence (ECL) sensor based on the ECL amplifying behavior of the graphene quantum dots-CdS nanocrystals (GQDs-CdS NCs) was constructed for the detection of pentachlorophenol (PCP). Because of the presence of doped GQDs, the resulting GQDs-CdS NCs exhibited 5-fold enhanced ECL intensity than pure CdS NCs with the ECL onset potential positively shifted by 80 mV. Furthermore, based on the effective inhibition of the ECL response of GQDs-CdS NCs film by PCP, a simple method for ultrasensitive determination of PCP was devised, which showed a wide linear range of 0.01-500 ng mL(-1) and a low detection limit of 3 pg mL(-1) (S/N = 3) with good stability, reproducibility and applicability for PCP detection in real water samples. Thus, it can be expected that GQDs-based composites with excellent performance may play a more important role in pesticide determination.