Improved SERS performance of a silver triangular nanoparticle/TiO2 nanoarray heterostructure and its application for food additive detection

A novel Ag triangle nanoparticles/TiO2 nanorod array (AgNTs/TNA) heterostructure was designed as a surface-enhanced Raman scattering (SERS) active substrate for the sensitive detection of Rhodamine 6G (R6G), Crystal Violet (CV), Malachite Green (MG) and Thiram in food samples. The heterostructure was constructed by simply stacking AgNTs and hydrothermally prepared rutile TNA together. On the surface of the heterostructure, the intensity of the Raman scattering intensity was about two times stronger compared with that on the AgNT substrate, using the R6G molecule as a probe. The AgNTs/TNA heterostructure could detect the SERS signal of R6G down to 10−10 M, showing excellent SERS performance. This platform has been successfully applied for the detection of CV and MG residues in crayfish. When irradiated with ultraviolet light, the SERS substrates can be cleaned and reused. This work demonstrated that the AgNTs/TNA metal–semiconductor heterostructure with high sensitivity, reproducibility and recyclability could provide an alternative reliable platform for food additive analysis.