**5. Summary**

In this chapter, it is introduced that although persistent organic pollutants such as PCBs are difficult to detect at trace amount, they can be detected and recognized rapidly via the SERS technique. Ag nanostructured SERS substrates prepared by the glancing angle deposition method are excellent at detection and their sensitivity can be further improved by tuning the thin underlayer films. With well designed and prepared Ag nanostructured SERS sub‐ strates, pentachlorinated biphenyl molecules are detected and recognized at trace level us‐ ing the SERS method. These series of studies provide a potential method for trace pollutant detection via silver nanostructure.
