Construction of A Nanozyme-based Sensing Array for High-Throughput Identification of Organophosphorus Pesticides in Chinese Medicinal Materials

A multi-channel colorimetric sensor array based on poly(amidoamine) dendrimers (PAMAM)-modified silver oxide (Ag2O) nanocomposites (Ag2O@PAMAM) was developed in this work. Through hydroxyl group modified PAMAM, the water dispersibility of Ag2O was significantly improved, thereby effectively addressing the issue associated with the aggregation and inactivation commonly observed in traditional Ag2O nanozymes. Leveraging the specific inhibitory effect of organophosphates (OPs) on nanozyme activity, a cross-reactive sensing interface was constructed by integrating the distinct responses of three chromogenic substrates such as 3,3′,5,5′-tetramethyl benzidine (TMB), o-phenylenediamine (OPD), and 2,2′-azinobis-(3-ethylbenzthiazoline-6-sulphonate (ABTS) with the pattern recognition algorithms for multi-channel signal analysis. Experimental results demonstrated that the sensor array successfully achieved simultaneous discrimination and detection of five representative OPs, including parathion-methyl, chlorpyrifos, dichlofenthion, phoxim and glyphosate, in the complex matrix of Scutellaria baicalensis, a commonly used traditional Chinese medicine. This strategy provided a novel and effective platform for high-throughput screening of multi-residue pesticides in complex traditional Chinese medicine systems, combining both a stable sensing interface and advanced pattern recognition capabilities.