Silver nanoparticle-assembled micro-bowl arrays for sensitive SERS detection of pesticide residue.

It is of great significance to develop a simple and effective method for constructing large-scale high-quality surface-enhanced Raman scattering (SERS) substrate. Here, an Ag nanoparticle-assembled micro-bowl array was prepared by a close-packed polystyrene (PS) sphere monolayer templated electrodeposition approach. The fabricated Ag nanoparticle-assembled micro-bowl array shows high SERS sensitivity to rhodamine 6G (R6G) under an ultra-low concentration of 1 fM, and exhibits excellent SERS spectral uniformity with a small relative standard deviation (RSD) of 7.6% and good reproducibility (a RSD ∼8.2% for the average peak intensities from different batches of SERS substrates). The fabricated micro-bowl array SERS substrate was employed to detect pesticide residue (thiram and methyl parathion) on vegetables. The limit of detections (LODs) for the two pesticides are lower than the maximum residue limits (MRLs) set by the European Union respectively, showing promising application in rapid inspection of food safety.