Análisis cuantitativo de una mezcla binaria a partir de datos espectrofotométricos UV usando un método alterno

Abstract

This work describes a laboratory exercise useful for an instrumental analysis course. In the exercise, an alternative method is applied to carry out the quantitative analysis of a binary mixture from UV spectrophotometric data. For this purpose, a mixture with known concentrations of 4-aminobenzoic acid and nicotinic acid was prepared, its absorbances at several wavelengths in the interval of 242 to 330 nanometers were recorded, and the resulting data were subjected to the alternative procedure. In this one, a simple transformation on the absorbance equation of the mixture is applied to obtain a linear relationship from which the concentrations of the components are calculated. In spite of its simplicity, the method produces a very good agreement between the calculated concentrations and the actual ones, errors within 2% have been found. The exercise provides an interesting alternative to the conventional procedure customarily taught in an instrumental analysis course.