Improved surface-enhanced Raman scattering on micro-scale Au hollow spheres: Synthesis and application in detecting tetracycline

Abstract

Au nanoparticles (NPs) forming a Au shell are coated on the surfaces of Ni microparticles (MPs) through a simple redox-transmetalation reaction, forming Ni/Au core-shell MPs. Then Au hollow spheres (HSs) are prepared by etching the Ni core in 1 mol L⁻¹ HCl solution. Surface-enhanced Raman scattering (SERS) spectroscopy signals of typical analytes such as rhodamine 6G (R6G) are observed on micro-scale Au HSs, even though the concentration of the analyte is as low as 10⁻¹⁵ mol L⁻¹ (R6G). The Au HSs are also applied to detect tetracycline (TC), and a strong SERS signal is observed with the TC concentration of 0.1 μg L⁻¹. The quantitative analysis can be performed at 1595 and 1320 cm⁻¹, and a good linear response is also obtained. This work provides a potential and unique technique to detect broad-spectrum polyketide antibiotics in the future, and the detection of TC in foods and milk can also be performed using this SERS-based Au HSs substrate, which will benefit human health.