Kinetic measurement of autoxidation in carotenoids by X-ray diffraction: a new, rapid, and reliable method

X-ray powder diffractometry has been used for the kinetic study of autoxidation by atmospheric oxygen of synthetic carotenoids at different temperatures (heterogeneous reactions). Peak intensity of a selected diffraction maximum was chosen as a kinetic variable. The results found for β-apo-8′-carotenal, C₃₀H₄₀O, showed that X-ray diffraction can be a rapid, simple, and reliable method for the kinetic analysis of autoxidation of carotenoids and perhaps for other materials in the solid state. This could open new perspectives in the study of this type of reaction.