Surface‐Enhanced Raman Spectroscopic Analysis of Anatase Titanium Dioxide Nanoparticles: Investigation of the Key Factors

Abstract

AbstractCharacterization of titanium dioxide nanoparticles (TiO2‐NPs) is significant to ensure its quality and safety in applications and facilitate risk assessment. Surface‐enhanced Raman spectroscopy (SERS) is a novel technique for characterization of the size of TiO2 particles. Herein, we investigated the key factors in the SERS analysis of anatase TiO2‐NPs using a variety of well‐characterized particle reference materials (8–173 nm) and gallocyanin (GLN) as a ligand for SERS. The result shows that regardless of the particle and ligand concentrations used, the R‐value obtained from the ratio of TiO2 (144 cm−1) to GLN (1639 cm−1) peak intensities was able to distinguish between the nano‐sized particles from the micro‐particles, although no significant difference was observed between 8 to 65 nm particles. This means particle size is the primary factor that affected the R. The concentration of the NPs and the ligand, respectively, could also affect the R as secondary factors and common dispersion methods such as adjusting the pH and the sonication did not affect the R. However, this method did not work in presence of a stronger binding dispersing agent such as sodium pyrophosphate (SPP). This study fulfilled the knowledge gap regarding the key factors that impacts the SERS analysis of TiO2‐NPs which will facilitate the further application of this technique in the analysis of TiO2‐NPs in food products and environmental matrices.