Derivapress is a TLC plate chemical derivatization device. It allows the application of the derivatization reagent on the TLC plate, with optimal conditions of uniformity, safety, and environment preservation. Contrary to spray techniques, the uniformity of the distribution of the reagent by Derivapress allows quantitative post-derivatization TLC analysis. Derivapress is particularly useful in Pharmaceuticals, Cosmetics, Chemicals, Food, and Biological applications.