Resumen de Mixture Design Experiments Applied to the Formulation of Colorant Solutions
J. M. Gozálvez Zafrilla, J. C. García Díaz
The "design of experiments" (DOE) has great importance in the chemical industry as a tool to optimize processes or product characteristics and should be included in undergraduate chemical education. DOE is used to empirically describe the influence of relevant variables (factors) on variables of the studied phenomenon (response variables). A particular case of DOE is the mixture design, where the factors are the component fractions and the responses are any characteristics of the mixture. In this article a simple laboratory that employs the mixture design is proposed to relate the proportions of predefined pure colorant solutions with the resulting color of the mixture. Three colorant solutions (tartrazine, Ponceau 4R, and indigo carmine) are mixed in different proportions and the resulting mixtures are analyzed by a spectrophotometer to obtain the color coordinates. By statistical analysis of the color a response function that relates the fractions of each solution to the resulting color is obtained. With this laboratory, students learn how to use DOE techniques to plan the appropriate experiments. In addition, students use concepts related with color measurement.
