|Persistent Organic Pollutants (POPs) pose a big threat to human beings and the environment. POPs are highly toxic and persistence, and can travel long distance in the environment and bio-amplify through the food-chain, so even small exposures may eventually reach dangerous levels. Traditional techniques for detecting POPs include gas chromatography, immunoassays, ion detection technique, and high-resolution mass spectrometry. However, these large-scale sophisticated analytical instruments are usually used in centralized laboratories, and not suitable to move here and there for real-time field-deployable detection. Therefore low-cost in situ rapid detection of trace-level POPs is extremely important.
Surface-enhanced Raman scattering/spectroscopy (SERS) is a powerful tool for rapid identification of analytes with high sensitivity and fingerprint characteristics. Therefore with the help of Portable or Handheld Raman Spectrometer, SERS has potentials in rapid detection of trace POPs. One of the key issues in SERS-based detection is the building of effective substrates with enough SERS “hot spots” to ensure both high sensitivity and excellent SERS signal reproducibility. As highly ordered noble metal nano-arrays usually contain uniformly distributed nano-gaps, sharp-tips/edges, which may produce highly concentrated electromagnetic fields associated with strong localized surface plasmon resonance so that SERS “hot spots” will occur at these positions. On the other hand some semiconductors have chemical supporting Raman enhancement. Based on these points of view we have built various metal/semiconductor nano-arrays with remarkable SERS sensitivity and signal reproducibility for various POPs [1-9], paving the way to the SERS-based rapid field-deployable detection of trace-level POPs.