Synthesis of a 3D Ag-Decorated Chitosan Film As a Simple and Stable Flexible SERS Substrate for the Detection of Pesticides in Food

We report a low-cost, shape-adaptable, and stable 3D porous surface enhanced Raman scattering (SERS) film–substrate, on which silver nanoparticles (Ag NPs) were loaded. The SERS substrate could not only be directly immersed in Nile blue A (NBA) solution for detection but also detect triazophos in food by wiping the analytes on solid surfaces. A broad linearity range of 0.2–1 ppb and a low limit of detection of 80 ppt were achieved for a triazophos solution. The substrate was stable and exhibited a high sensitivity after 5 weeks of storage at room temperature. In addition, the substrate has been successfully applied to the detection of practical samples of apples, cabbage, lettuce, and green onions. Thus, this simple and highly efficient SERS substrate may have great potential in pesticide-sensing applications.