Lithopone is rather nontoxic, due to the insolubility of its components. It has been used in medicine as a radiocontrast agent. Lithopone is allowed to be in contact with foodstuffs in the US and Europe.

Made Safe only allows titanium dioxide as part of sunscreen solutions and diaper creams; all titanium dioxide must be non-nanoparticle. Made Safe does not allow titanium dioxide in any other personal care or household products.

In the manufacturing industry, sometimes many products require coloring, and the ideal coloring material is lithopone. This is a product manufactured through chemical methods. It is a mixture of barium sulfate and zinc sulfide. When the product contains more zinc sulfide, its effect will be better, that is, the coloring ability will be more stable. If you want to buy high-quality lithopone, you have to understand its properties and characteristics. Today’s article will give you a detailed understanding of lithopone.

A dense, white, opaque pigment composed of a mixture of Zinc sulfide (30%) and Barium sulfate (70%) with trace amounts of Zinc oxide. Lithopone, first produced in 1874, was called Orr's white. The mixture of the two components is so intimate that it is hard to distinguish microscopically. Lithopone is an inert, transparent pigment which is often used as a filler or as a base for lake pigments. Lithopone was widely used in house paints in the first half of the 20th century. It was also used for some artist grounds, inks and as a filler in Paper, Leather, and Linoleum. Now lithopone has mostly been replaced by Titanium dioxide.

Titanium dioxide particles help light scatter and reflect, Kelly Johnson-Arbor, MD, a medical toxicology physician at the National Capital Poison Center, told Health. Because of that, we often use it as a whitening agent.

Although barium sulfate is almost completely inert, zinc sulfide degrades upon exposure to UV light, leading to darkening of the pigment. The severity of this UV reaction is dependent on a combination of two factors; how much zinc sulfide makes up the pigments formulation, and its total accumulated UV exposure. Depending on these factors the pigment itself can vary in shade over time, ranging from pure white all the way to grey or even black. To suppress this effect, a dopant may be used, such as a small amount of cobalt salts, which would be added to the formulation. This process creates cobalt-doped zinc sulfide. The cobalt salts help to stabilize zinc sulfide so it will not have as severe a reaction to UV exposure.

This constant high rate of ROS production leads rapidly to extreme macromolecular oxidation, here it is observed in the AOPP and MDA detected after 3 h in samples treated with bare P25TiO₂NPs (Fig. 6, Fig. 7). Macromolecular oxidation includes, among others, both protein and lipid oxidation. The ROS causes protein oxidation by direct reaction or indirect reactions with secondary by-products of oxidative stress. Protein fragmentation or cross-linkages could be produced after the oxidation of amino acid side chains and protein backbones. These and later dityrosine-containing protein products formed during excessive production of oxidants are known as advanced oxidation protein products (AOPP). They absorb at 340 nm and are used to estimate the damage to structural cell amino acids. Lipid oxidation is detected by the conjugation of oxidized polyunsaturated lipids with thiobarbituric acid, forming a molecule that absorbs light at 532 nm. Polyunsaturated lipids are oxidized as a result of a free-radical-mediated chain of reactions. The most exposed targets are usually membrane lipids. The macromolecular damage could represent a deadly danger if it is too extensive, and this might be the case. Moreover, it could be observed that cellular damage continues further and becomes irrevocable after 6 h and MDA could not be detected. This may be due to the fact that the lipids were completely degraded and cells were no longer viable. Lipids from the cell membrane are the most prone to oxidation. In fact, lipid peroxidation biomarkers are used to screen the oxidative body balance [51]. At the same time, AOPP values are up to 30 times higher for bare nanoparticles in comparison to the functionalized ones.

For the Fourth Quarter of 2021

Conclusion

For research published in 2022 study in the journal Food and Chemical Toxicology, scientists examined “the genotoxicity and the intracellular reactive oxygen species induction by physiologically relevant concentrations of three different TiO2 nanomaterials in Caco-2 and HT29-MTX-E12 intestinal cells, while considering the potential influence of the digestion process in the NMs’ physiochemical characteristics.” They found a “DNA-damaging effect dependent on the nanomaterial,” along with the micronucleus assay suggesting “effects on chromosomal integrity, an indicator of cancer risk, in the HT29-MTX-E12 cells, for all the tested TiO2 nanomaterials.” Researchers concluded that the results showcase “evidence of concern” regarding titanium dioxide used as a food additive.

The raw material used in this method is FeSO4. In order to maintain the Fe3 + concentration in the reaction medium in a specific range, reducing agent iron sheet is added in the reaction process. Iron yellow crystal seed was added and air was introduced to synthesize iron yellow under certain pH conditions. The method mainly includes two steps: (1) firstly, FeSO4 · 7H2O is used as raw material, NaOH or NH3 · H2O is used as precipitant or pH regulator, and air is used as oxidant to prepare crystal seed; (2) Iron yellow is produced by two-step oxidation with crystal seed, FeSO4, iron sheet and air.

The Scientific Committee on Consumer Safety issued an opinion of the safety of titanium dioxide in food, stating that it should no longer be considered as safe when used as a food additive.