Urchin-like LaVO₄/Au composite microspheres for surface-enhanced Raman scattering detection.

The availability of sensitive, reproducible and stable substrate is critically important for surface enhanced Raman scattering (SERS)-based application, but it still remains a challenge up to now. In this work, urchin-like LaVO4 microspheres prepared by a hydrothermal method were used as a template to fabricate SERS substrate by deposition of Au nanoparticle onto the surfaces of LaVO4 microspheres. The coverage of Au nanoparticles on the surfaces of LaVO4 microspheres can be easily controlled by varying the amount of Au precursor. SERS measurement showed that the coverage of Au nanoparticles on the surfaces of LaVO4 microspheres had a great effect on SERS activity. The SERS signals collected from 80 microspheres indicated that as-prepared SERS substrate exhibited a good reproducibility. Detection of melamine molecules with a low concentration (1.0×10(-9)M) was used as an example to show the possible application of such substrate. In addition, the effect of iron ion (Fe(3+)) on detection melamine from the mixture of melamine and benzoic acid was also investigated. It was found that the interference of benzoic acid in detecting melamine from the mixture can be removed by adding Fe(3+).