Luminescent hydrogel-enabled electrochemiluminescent aptasensor and portable analyzer for on-site quantification of acetamiprid in vegetables.

Abstract

Acetamiprid residues in vegetables threaten human health and food safety, necessitating rapid, sensitive detection. Electrochemiluminescence (ECL) is highly sensitive but suffers from matrix-induced quenching and high-voltage photomultiplier tubes (PMT). Here we co-load N-(4-aminobutyl)-N-ethylisoluminol (ABEI), MnO2 nanosheets (MnO2NSs), and gold nanoparticles (AuNPs) into a three-dimensional polyethyleneimine-glutaraldehyde (PEI-GA) hydrogel and integrate it with a graphene oxide-aptamer interface to form an ECL aptasensor for acetamiprid. The ion-permeable 3D scaffold shortens mass-transport pathways, promotes reactive oxygen species generation, and increases the distance between luminophores and quenchers, affording approximately 20% higher ECL intensity than an equivalent MnO2NSs@ABEI@AuNPs nanostructured film at the same loading and potential window. Coupling this hydrogel aptasensor with a low-supply-voltage portable ECL analyzer based on a silicon photomultiplier (SiPM) yields a signal-enhanced platform with a linear range of 1.0 × 10-3-1.0 × 103 nM, a detection limit of 0.3 pM, and excellent reproducibility (RSD < 3%). Using QuEChERS pretreatment, the sensor provides high recoveries for acetamiprid spiked into spinach, celery, and Chinese chives, with results that correlate closely with those obtained by liquid chromatography-tandem mass spectrometry (LC-MS/MS). This work presents a practical strategy for integrating a luminescent hydrogel with a low-supply-voltage portable ECL analyzer for high-sensitivity detection of acetamiprid in complex vegetable matrices.