A Dual-Mode Electrochemical Aptasensor for Ultrasensitive Detecting Acetamiprid Based on Hollow Porous Fe2O3 Cubes

Acetamiprid, a widely utilized pesticide, poses risks to human health due to the bioaccumulation of its residues. Detecting pesticide residues is crucial for effective pesticide management. To enhance the sensitivity and accuracy of pesticide detection, researchers have developed dual-mode sensors that allow for mutual validation of the two signals. In this paper, a dual-mode electrochemical sensor for detecting acetamiprid was constructed using H₂O₂ and methylene blue (MB) as probes. The electrochemical signal of MB was measured using square wave voltammetry (SWV) mode, followed by the detection of the reduction signal of H₂O₂ in amperometric i-t curve (i-t) mode. The two signals complemented each other, thereby reducing errors and enhancing measurement accuracy. Additionally, hollow porous Fe₂O₃ cubes were synthesized to catalyze the reduction of H₂O₂ to enhance mass transfer rates. The detection limit in SWV mode was 0.034 pM (S/N = 3), with a linear equation represented as ΔI = 5.39lgc-33.80 (R² = 0.99) within the concentration range of 0.1 pM to 0 .1µM. The detection limit in i-t mode was 0.38 nM (S/N = 3), with a linear equation expressed as ΔI = -7.26lgc-77.20 (R² = 0.99) within the concentration range of 0.1 nM to 0.1 µM. This dual-mode electrochemical sensor offers a promising approach for detecting pesticide residues.