An electrochemiluminescence sensor for sensitive detection of malathion based on g-C₃N₄-CdTe composite nanomaterials

A self-enhanced electrochemical luminescence (ECL) composite material g-C₃N₄-CdTe QDs was prepared. The combination of g-C₃N₄ and CdTe QDs can amplify the ECL signal and improve the stability. Based on this discovery, g-C₃N₄-CdTe QDs and acetylcholine esterase (AChE) were used to construct an ECL sensor for organophosphorus pesticides (OP) detection. The sensor showed a strong initial ECL signal in PBS containing S₂O₈^2-. It is because that g-C₃N₄ not only acts as a co-reaction promoter to amplify the ECL signal of the CdTe QDs/S₂O₈^2- system but also acts as a carrier with large specific surface area to adsorb more CdTe QDs and improve the sensitivity of the sensor. The reaction of AChE and acetylthiocholine (ATCl) was hindered by organophosphorus pesticides (OPs). The ECL signal was enhanced by the addition of OPs, and a linear relationship was displayed between the increasing value and the concentration of malathion. A good linear range from 2.52 × 10^-13 to 2.52 × 10^-8 mol L^-1 was obtained and the limit of detection was 8.4 × 10^-14 mol L^-1 under optimized experimental conditions. The results indicated that the sensor had promising applications for the detection of OPs in vegetable samples.