The FDA's Code of Federal Regulations allows for the legal, regulated use of titanium dioxide in food products, under some restrictions.
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.
This article discusses the discovery of phosphorescent lithopone on watercolor drawings by American artist John La Farge dated between 1890 and 1905 and the history of lithopone in the pigment industry in the late 19th and early 20th centuries. Despite having many desirable qualities for use in white watercolor or oil paints, the development of lithopone as an artists’ pigment was hampered by its tendency to darken in sunlight. Its availability to, and adoption by, artists remain unclear, as colormen's trade catalogs were generally not explicit in describing white pigments as containing lithopone. Further, lithopone may be mistaken for lead white during visual examination and its short-lived phosphorescence can be easily missed by the uninformed observer. Phosphorescent lithopone has been documented on only one other work-to-date: a watercolor by Van Gogh. In addition to the history of lithopone's manufacture, the article details the mechanism for its phosphorescence and its identification aided by Raman spectroscopy and spectrofluorimetry.
