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.

In response to the allegations, Justin Comes, vice president of research and development at Mars Wrigley North America, told Health that safety is of paramount importance to Mars Wrigley. While we do not comment on pending litigation, all Mars Wrigley ingredients are safe and manufactured in compliance with strict quality and safety requirements established by food safety regulators, including the FDA.

What are the different forms of titanium dioxide in beauty and personal care products?

The analysis of the supernatant by UV–Vis spectrometry showed that each gram of P25TiO₂NP is loaded with 0.17 g of vitamin B2, after washing them. This value is coherent with the thermogram (Fig. 1), which showed a loss of 19% of weight, attributed to the thermal decomposition of vitamin B2.