Ultraviolet radiation from the sun is responsible for increased rates of skin cancer. To prevent sunburn and to reduce the chance of skin cancer, sunscreen products have been developed to reflect or absorb ultraviolet radiation. Metal oxides such as titanium dioxide and zinc oxide are added to sunscreens to reflect ultraviolet radiation. The term Sunblock is often used where titanium dioxide and/or zinc oxide are part of the formulation.
Traditionally, the analysis of titanium dioxide is very difficult due to the insolubility of titanium dioxide in most solvents. Most analytical techniques involve the hazardous digestion of titanium dioxide in very concentrated acids like sulfuric, nitric or hydrofluoric acids. This preparation is then followed by dilution and then analysis by Inductively Coupled Plasma Optical Emission spectrometry (ICP-OES) or Atomic Absorption Spectrometry (AAS). An alternate option is to further treat the digested solution with hydrogen peroxide to produce a yellow color which is measured at 410 nm by UV visible photo spectrometer.