Determination of iron content using the PhotoMetrix PRO® application: Technology in favor of teaching chemistry

Abstract

Information and Communications Technology in the teaching of chemistry has been a trend in the field of education, especially when the teacher aims to increase student interest and raise the quality of the classes. In this work, the PhotoMetrix PRO® app, free and available for smartphones, was used to in a colorimetry practice to measure iron by the reaction with thiocyanate. Spectrometer set at visible range is used to monitoring this reaction. At practical classes in high school, in technical and undergraduate courses the number of equipment is generally insufficient for handling by the students, and in many institutions, they are not available. The methodology was adjusted with a focus on sustainability at the chemistry laboratory, by using reduced volumes of reagents to mitigate the generation of waste and the analysis costs. The methodology presented R2 values of 0.999, detection and quantification limits of 0.34 e 0.98 mg L-1, respectively, and 6.0 % RSD. Iron content was measured in three samples, namely tap water, razor blade and food supplement. The level of iron was satisfactory, compared to visible-spectrophotometry results.