High reliable and robust ultrathin-layer gold coating porous silver substrate via galvanic-free deposition for solid phase microextraction coupled with surface enhanced Raman spectroscopy.

That intense demand for both high sensitivity and high reliability has been a key factor strengthening the surface enhanced Raman spectroscopy (SERS) in the analytical application, particular in the hyphenation with pre-concentration technique. Credible data acquisition and processing is very dependent on the stable and uniform performance of SERS-active substrate. Here, a reliable and uniform ultrathin-layer Au was proposed for protecting the porous Ag fiber (porous Ag@Au) and applied in the solid phase microextraction coupled with SERS. The Au layer was carefully deposited on porous Ag surface to form the uniform film by a galvanic-free displacement reaction. This coating endowed the substrate with high oxidation-resistance under heating and good durability in the atmosphere condition. The extraction and SERS performance of Nitrofurazone and Semicarbazide were investigated on this fiber, the bands at 1350 cm and 1387 cm were selected as the characteristic peaks for quantitative determination, respectively. This robust and sensitive substrate provide the high enhancement factor of 1.3 × 10 and low LOD of 5.1 ppb for the extraction and identification of Nitrofurazone compounds. Importantly, this work develops a versatile strategy for rapid detection of prohibited antibiotic and its marker residue in a complex matrix.