Rapid Identification and Quantification of Aqueous Antibiotics over a Machine Learning-Integrated Raman Sensor Array

Surface-enhanced Raman spectroscopy (SERS) is a promising technique for on-site detection of aqueous pollutants, whereas single-substrate SERS suffers from low separability of analogous compounds and poor accuracy. Here, we propose a multisubstrate SERS fusion strategy to elevate the dimension of SERS information based on machine learning (ML) integration. An array of SERS substrates fabricated through modifying Au nanoparticles with polyvinylpyrrolidone, l-cysteine, and 3-mercaptopropionic acid exhibits two responsive modes (peak superposition and signal succession) toward three sulfonamide antibiotics. Moreover, ML models developed on multi-interface concatenated spectra (MICS) enable simultaneous identification and quantification of the sulfonamide antibiotics, outperforming any of the single substrates. The classification accuracy increased from 95-96% to 99.6% for single pollutants and 82.2-92.2% to 96.7% for mixtures, respectively, while the quantitative prediction achieved R2 up to 0.99 with markedly reduced prediction errors. The method is validated in river water, lake water, and municipal wastewater secondary effluent, yielding recoveries of 75.5-116% (median 97.5%), with 23/27 measurements within 80-110%, and an overall turnaround of ∼30 min from sample preparation to readout. Through coupling the dual-mode responsive Raman sensor array with data-driven modeling, this work provides a paradigm of rapid and multianalyte SERS analysis of structurally similar pollutants for on-site environmental monitoring.