The editors of the journal Physics and Chemistry of Solid State published the current issue last week. Among the articles of Ukrainian and foreign scientists is an article written by student of Chemistry Department Nazariy Danyliuk. The paper is devoted to the usage of a smartphone for studying the photocatalytic oxidation kinetics. The correct choice of substrate (fluorescent dye Rhodamine B) makes it possible to determine the concentration comparing the bright pink color of the dye with a white suspension of photocatalyst (titanium dioxide). A high-quality smartphone camera allows to register color and calculate the concentration of dye quickly.