Detection of profenofos based on an aptamer-regulated luminol-Au@CeO

A dual-mode sensor is presented based on a luminol-Au@CeO2 nanozyme for the highly sensitive and selective detection of profenofos, thereby overcoming prior limitations and significantly enhancing detection reliability. This nanocomposite acts as an efficient co-reaction promoter in the luminol-H2O2 electrochemiluminescence (ECL) system by catalyzing the decomposition of H2O2 to generate abundant superoxide anion radicals (O2•−), thereby amplifying the anodic ECL signal. To achieve specific recognition, a thiolated aptamer was anchored onto the electrode surface. The binding of profenofos induces a conformational change in the aptamer, which in turn hinders the catalytic activity of luminol-Au@CeO2 and leads to a decrease in the ECL signal. In the ECL mode, profenofos detection exhibited a linear response from 0.01 to 1000 ng·mL− 1, with a detection limit of 8.3 pg·mL− 1 (S/N = 3). In parallel, the O2•− generated by the nanozyme also catalyzes the oxidation of colorless 3,3’,5,5’-tetramethylbenzidine (TMB) to blue oxTMB, providing a colorimetric readout. The colorimetric detection was achieved by monitoring the decrease in absorbance at 652 nm induced by aptamer-profenofos binding, yielding a linear range of 10 to 400 ng·mL− 1 and a detection limit of 6.3 ng·mL− 1. The dual-mode sensor was successfully employed in the quantification of profenofos in vegetable samples, demonstrating high accuracy, good reproducibility, and great potential for reliable monitoring of pesticide residues in food safety applications.