Electrochemiluminescence-smartphone colorimetric dual-mode sensor driven by SnS2 quantum dots and Ag2O nanozyme for sensitive detection of sulfadiazine

An ECL-smartphone colorimetric dual-mode sensor is developed using SnS 2 QDs and Ag 2 O nanozyme. • SnS 2 QDs exhibit high and stable ECL intensity for durable detection. • Ag 2 O nanozyme catalyzes TMB oxidation, in free of H 2 O 2 . • This sensor achieves high-sensitivity detection to suppress false positives. Sulfadiazine (SDZ), a widely used antibiotic, poses a serious residue threat to food safety, necessitating the development of rapid, sensitive, and reliable detection. Here, a dual-mode sensor combining electrochemiluminescence (ECL) and smartphone-based colorimetry is developed using SnS 2 quantum dots (QDs) as the ECL emitter and Ag 2 O nanozyme as the 3,3′,5,5′-tetramethylbenzidine (TMB) coloring catalyst. This dual-mode platform, which features a molecularly imprinted polymer (MIP)-SDZ-aptamer sandwich configuration, combines the high sensitivity and wide dynamic range of ECL with the simplicity, visual readability, and portability of smartphone-based colorimetric analysis. The sensor exhibited high sensitivity in a wide linear range (10 −4 –10 3  μM) with a low detection limit (5.8 × 10 −5  μM, S/N = 3). Spiked recovery tests in real chicken samples confirmed its high accuracy and reliability. This work not only provides a convenient, low-cost, and accurate method for SDZ detection but also offers a new strategy for the potential application of multimodal sensing platforms in food safety monitoring. Download: Download high-res image (147KB) Download: Download full-size image