Titanium Dioxide in Food Products: Quantitative Analysis Using ICP-MS and Raman Spectroscopy

Titanium dioxide (TiO2) is commonly used as a color additive in food products. In this study, a total of 11 food products, such as a coffee cream, yogurt snack, hard candy, and chewy candy, that are widely consumed by adults or children were investigated. For characterization of particle size, size distribution, crystallinity, and concentration of TiO2, particles were first extracted using an acid digestion method from food, and various analytical techniques were applied. All products investigated in this study contained nanosized TiO2 particles (21.3-53.7%) in the anatase phase. The particle size of TiO2 was in the range of 26.9-463.2 nm. The concentration of TiO2 in the products ranged from 0.015% (150 ppm) to 0.462% (4620 ppm). These values obtained using inductively coupled plasma mass spectrometry (ICP-MS) were considered as the reference and were compared with Raman results to evaluate the feasibility of using the Raman method to quantitate TiO2 in food products. The Raman method developed in this study proved to effectively analyze anatase TiO2 in food products at levels of several hundred parts per million or greater. Limitations of using the Raman method as a quick screening tool for determination of TiO2 are also discussed.