Non-enzymatic signal-on electrochemiluminescence detection of organophosphorus pesticides based on tungsten disulfide quantum dots

Abstract

The rapid and efficient identification and quantification of neurotoxic organophosphorus pesticides (OPs) are crucial for ensuring environmental safety and human health. However, the current acetylcholinesterase OP sensors are largely limited by the stability and cost of bio-enzymes, as well as the occurrence of false negatives in “signal-off” strategies. In this study, we present a pioneering approach that utilizes high-performance electrochemiluminescence (ECL) of tungsten disulfide quantum dots (WS₂ QDs) to develop an alternative sustainable non-enzymatic ECL sensor for “signal-on” OP detection. The presence of phosphate esters in OPs efficiently mediates ECL enhancement of WS₂ QDs using K₂S₂O₈ as a coreactant. With this new strategy, we achieved highly sensitive and selective detection of common OPs, including methyl parathion, naled, dimethoate, and malathion, with detection limits of 1.48 pg mL⁻¹, 4.30 pg mL⁻¹, 0.35 pg mL⁻¹, and 5.58 pg mL⁻¹, respectively. When applied to river water and spinach samples, the sensor also demonstrated high reproducibility and good recovery. The electrochemical hydrolysis decomposition of OPs during the detection process in this study provides a “two birds with one stone” strategy, serving the dual objective of identifying and degrading OPs. This work paves a new avenue for direct ECL sensing in environmental and food screening, eliminating the reliance on common indirect biological identification elements.