High-performance ratiometric magnetic electrochemical sensor for acetamiprid detection using Ag@PDA@Fe3O4 nanocomposites

Acetamiprid (AAP) is a renowned neonicotinoid insecticide for swift insect control that is prone to residue in agricultural products and threatens human health. Magnetic electrochemical sensor (MES) was developed for high-precision detection of AAP based on silver nanoparticle (AgNPs) and polydopamine (PDA) modified Fe3O4 nanocomposites (Ag@PDA@Fe3O4). The electrochemical signals generated by AAP hydrolysis and AgNPs oxidation are respectively used as two special signal sources. An increase in AAP concentration led to a proportional increase in the signal from AAP hydrolysis at +0.9 V (IAAP), while the signal from AgNPs oxidation at +0.27 V (IAg) correspondingly decreased. The output signal Delta I AAP / Delta I Ag (R2=0.9890) demonstrates a superior linear relationship compared to Delta I AAP (R2=0.9790) or Delta I Ag (R2=0.9740) alone. MES demonstrated a broad linear detection range from 0.01 to 2.00 mg L- 1 and an impressive limit of detection (LOD, 3S/M) at 3.6 mu g L- 1 . The incorporation of magnetic glassy carbon electrodes (MGCE) significantly mitigates the detachment of nano- materials. MES has excellent stability and selectivity, and can successfully detect AAP in actual cowpea samples. This study provides pivotal insights into the design of nanomaterial-based ratiometric electrochemical sensors for the sensitive and selective detection of AAP.