Rapid detection of TiO2 (E171) in table sugar using Raman spectroscopy

Abstract

ABSTRACTThe potential toxic effects of titanium dioxide (TiO2) to humans remain debatable despite its broad application as a food additive. Thus, confirmation of the existence of TiO2 particles in food matrices and subsequently quantifying them are becoming increasingly critical. This study developed a facile, rapid (< 30 min) and highly reliable method to detect and quantify TiO2 particles (E171) from food products (e.g., table sugar) by Raman spectroscopy. To detect TiO2 particles from sugar solution, sequential centrifugation and washing procedures were effectively applied to separate and recover 97% of TiO2 particles from the sugar solution. The peak intensity of TiO2 sensitively responded to the concentration of TiO2 with a limit of detection (LOD) of 0.073 mg kg–1. In the case of sugar granules, a mapping technique was applied to directly estimate the level of TiO2, which can be potentially used for rapid online monitoring. The plot of averaged intensity to TiO2 concentration in the sugar granules exhibited a good linear relationship in the wide range of 5–2000 mg kg–1, with an LOD of 8.46 mg kg–1. Additionally, we applied Raman spectroscopy to prove the presence of TiO2 in sugar-coated doughnuts. This study begins to fill in the analytical gaps that exist regarding the rapid detection and quantification of TiO2 in food, which facilitate the risk assessment of TiO2 through food exposure.