Journal: ACS Applied Nano Materials
Article Title: Hexagonal Au Nanostructure SERS Metasurface for AI-Driven Detection of Pesticide Residues in Real Food Samples
doi: 10.1021/acsanm.6c00433
Figure Lengend Snippet: Fabrication process and characterization of a honeycomb array, along with its application in QuEChERS-based pesticide analysis. (a) Substrate fabrication steps: (1) Coating the bottom metal layer via plasma-enhanced chemical vapor deposition (PECVD, (2) depositing the dielectric layer, (3) patterning the CSAR e-beam resist using EBL, (4) exposure followed by development, (5) coating the top metal layer through PVD, and (6) performing the lift-off process. (b) SEM image shows that the hexagonal structures are very regular (scale: 1 μm). (c) Main parameters that construct the 1-unit cell of hexagonal array. (d) The SEM image (left) and the EDS elemental density map (right) of the identical location are presented. The map on the right verifies that the elements Au, Si, Al, N, and C are distributed as intended within the surface design. (e) A diagram showing how to extract pesticides from cucumbers using the QuEChERS method: homogenization, extraction with acetonitrile, phase separation using QuEChERS salts, centrifugation, dispersive SPE cleaning, and making the final extract. (f) Schematic representation of Raman scattering utilizing a 785 nm laser beam focused on hexagonal structures arranged in a honeycomb array. (g–i) illustrates the average SERS intensities of 730 Raman shifts obtained on a blank cucumber matrix and their statistical fluctuations; also, relative standard deviation values calculated from 15 different measurement points are presented; a comparison of RSDs across three different production batches is made, and a heat map of 48 spectra obtained from blank cucumber matrix measurements is presented.
Article Snippet: Energy-dispersive X-ray spectroscopy (EDS) integrated with SEM (Oxford X_Max- JEOL JIB-4601F MultiBeam FIB-SEM) was employed to determine the elemental composition and distribution within the particles, confirming the fabrication fidelity and the realization of the designed Au HCA on the vertical MIM stack.
Techniques: Clinical Proteomics, Construct, Pesticides, Homogenization, Extraction, Centrifugation, Standard Deviation, Comparison