Ultrasensitive SERS detection of rhodamine 6G and p-nitrophenol based on electrochemically roughened nano-Au film.

Quantitative analysis of organic pollutants in environmental water is an important issue for ecological environment and human health. In this paper, the quantitative analysis of rhodamine 6G (R6G) and p-nitrophenol (PNP) is performed by the surface enhanced Raman scattering (SERS) technology. The enhancement of Raman signals is achieved on the surface of an electrochemically roughened nano-Au film. The SERS performance depends on the microstructure of roughened nano-Au films, which is affected by the thickness of Au films and electrochemical roughening parameters. The structure-dependence of SERS performance is validated by finite element simulation of local electromagnetic field distribution. An obvious SERS effect of R6G with an enhancement factor of 108 is obtained on the roughened nano-Au film. A sensitive SERS detection of R6G with a linear range of 10-9-10-5 M and a detection limit of 10-11 M is realized. Moreover, a wide linear range of 10-9-10-3 M is obtained for the detection of PNP. The roughened nano-Au film is an effective substrate for the SERS detection of organic pollutants with high reproducibility and good stability. Therefore, the electrochemical technology in this study is expected to be a very promising method for the fabrication of high-performance SERS substrate.