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

Abstract

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.

Preparation of TiO2 and Fe-TiO2 with an Impinging Stream-Rotating Packed Bed by the Precipitation Method for the Photodegradation of Gaseous Toluene

“…The Raman spectra of the prepared photocatalysts are shown in Figure 5b. The characteristic peaks at 141.6 cm −1 , 396.3 cm −1 , 516.4 cm −1 and 638.9 cm −1 correspond to the anatase phase [40,41], but there are no characteristic peaks of the rutile phase and iron-related phase except for the four peaks of the anatase phase. Compared with pure TiO 2 and Fe-TiO 2 , it is found that the Raman shift does not change after Fe 3+ doping, but the peak intensity and peak width change in varying degrees; in particular, the peak intensity of 5%Fe-TiO 2 decreases and the peak width increases, indicating that Fe 3+ replacing Ti 4+ in the lattice results in the increase of lattice distortion and peak width, while the inhibition of crystal transformation weakens the peak intensity.…”

Possible Adverse Effects of Food Additive E171 (Titanium Dioxide) Related to Particle Specific Human Toxicity, Including the Immune System

“…This examination assigns a larger fraction of TiO 2 particles present in pristine E171 to the nano-sized fractions than previously assumed. Analysis of food samples containing E171, via ICP-MS and Raman spectroscopy, showed anatase type TiO 2 particles in the range of 26.9-463.2 nm, with 21.3-53.7% of the particles in the nano-size fraction [31]. The determination of the nanoparticle fraction (Figure 1) within E171 is of importance since the size of particles is considered to be an important factor influencing toxicokinetics, toxicodynamics, and thus toxicity [8,21,32].…”

Characterisation of food grade titania with respect to nanoparticle content in pristine additives and in their related food products

“…It is likewise important to understand the impact of food processing on the extractability and characterisation of nanoparticles present in E171. Some research groups studied the size distribution of titanium dioxide particles in extracts from various food matrices by TEM (Weir et al 2012;Chen et al 2013;Peters et al 2014;Dudefoi et al 2017;Lim et al 2018) and single particle inductively coupled plasma mass spectrometry (sp-ICPMS) (Peters et al 2014;Candas-Zapico et al 2018). Given the unavailability of the starting (pristine) E171 materials in these studies, it was however not possible to verify whether the particle size distribution had been altered during the extraction process.…”