Flexible Au@AgNRs/MAA/PDMS-based SERS sensor coupled with intelligent algorithms for in-situ detection of thiram on apple

Thiram (THR) belongs to the dithiocarbamate family with a molecular formula of C6H12N2S4. THR represents one of the most common pesticides, used as an antifungal candidate worldwide. Notably, THR displays several intricate adverse impacts on living organisms' health. Therefore, the detection process of THR on fruit surfaces is critical for guaranteeing food safety. Herein, a flexible sensor coupled with intelligent algorithms was developed for the accurate and rapid in-situ detection of pesticide residues, in particular thiram on apple surfaces. A flexible sensor of surface-enhanced Raman spectroscopy (SERS) was constructed by assembling mercaptoacetic acid-modified core-shell gold-silver nanorods (Au@AgNRs/MAA) on an ammoniated polydimethylsiloxane (PDMS) layer. The high transparency and flexibility of the film enabled the in-situ collection of SERS signals. Subsequently, three intelligent algorithms were employed, and their performance in foretelling THR residues on apple surfaces was compared and evaluated. The competitive adaptive reweighted sampling (CARS) algorithm depicted the potent accurate forecasts, with a prediction correlation coefficient (Rp) of 0.9934 and a root mean square error of prediction (RMSEP) of 0.6969 mg/L. Since the suggested approach has the advantages of being simple, speedy, and sensitive, it will be a tremendous promise for quick and non-destructive examination of surface pollutants in the realm of food safety.