Fabrication of Al/Al2O3/Ag SERS substrate by the corrosion method to detect ketoprofen

Abstract

In this work, we studied and fabricated SERS substrate (surface-enhanced Raman scattering) substrates based on Al/Al₂O₃/Ag to detect ketoprofen solution at low concentrations. Silver nanoparticles were decorated on Al₂O₃/Al substrate due to a displacement reaction. By changing the volume ratios of hexadecyltrimethylammonium bromide (CTAB) to AgNO₃ and annealing temperature, the SERS substrates were fabricated with the large effective surface area, high density of ``hot-spots. The structure and surface morphology of these SERS substrates were investigated by measurements such as surface image recorded with scanning electron microscopy (SEM), energy dispersion X-ray spectroscopy at a point (EDS pointing), and X-ray diffraction analysis (XRD). The results showed that in the experimental condition of the ratio volume 1:1 between CTAB 0.01M and AgNO3 0.02M solutions, and the displacement reaction time of 30 minutes, annealed samples at 100oC in 2 hours were formed Al/Al₂O₃/Ag SERS platforms with nanostructure leaf-shaped. The Ag NPs with sizes of 10 - 50 nm were distributed homogeneously on the surface. The Raman signal of the sample showed that Al/Al2O3/Ag SERS substrates could detect rhodamine 6G (R6G) at a very low concentration at 10^-11M, analytical enhancement factor (EF) of ~ 8x10⁸. From that, this SERS substrate could be used to detect a ketoprofen solution at a concentration as low as 10 ppm with the enhancement factor of ~ 1.5x10⁶.