Flexible and Transparent SERS Substrates Composed of Au@Ag Nanorod Arrays for In Situ Detection of Pesticide Residues on Fruit and Vegetables

Due to the increasing importance of food quality/safety control, there is an imminent need to develop efficient methods for the rapid detection of pesticide residues in agricultural products. Herein, we proposed a simple and rapid detection approach to the in situ detection of residual pesticides on fruit/vegetable using surface-enhanced Raman spectroscopy (SERS). Flexible and transparent SERS substrates were fabricated by transferring Au@Ag core-shell nanorods (Au@Ag NRs) arrays to silicone membranes, with the single-layer Au@Ag NRs arrays prepared by the liquid–liquid interface self-assembly method. The as-prepared SERS sensor showed excellent SERS activity and repeatability, and it could be readily pasted onto the surface of fruit and vegetables for residual pesticide detection. For the inspection of thiram in contaminated strawberries, apples, and mushrooms, the limit of detection (LOD) could reach 2 ng/cm2 with high measurement recovery and reproducibility. In general, this work provides an effective way for the preparation and application of flexible and transparent SERS substrates in food-safety control.