Use of RGB as a Quantitative Method Applied to the Teaching of Analytical Chemistry

Abstract

Background: The use of alternatives for teaching analytical chemistry in undergraduate studies has been a challenge for teachers since most methods require high-cost equipment and functional analytical skills. This work presents the use of RGB, an additive color system n digital media, as a method of quantifying of a given analyte in samples. Aim: To analyze different samples containing different concentrations of coffee, comparing them using two techniques: 1) spectrophotometry and 2) RGB, and then perform the calculations for the determination of an unknown concentration. Methods: Eight samples were prepared, six with defined concentrations of coffee, one in white, and one without a defined concentration. Method 1 used the spectrophotometer to read the absorbance at 420 nm wavelength for melanoidin reading, in method 2 the RGB was used, positioning buckets in front of a digital screen emitting light at the corresponding wavelength. Microsoft Powerpoint was used to collect RGB and Microsoft Excel data for data processing. Results: The data obtained through the analytical equipment, as well as those obtained via RGB, were able to estimate the unknown concentration of coffee, both techniques estimated a concentration between 3 and 4%, both with the equation of the line and r² capable of estimating values corresponding to the concentrations of the samples. Discussion: The RGB technique has been studied in recent decades, mainly for colorimetric analyses, since it makes the study or laboratory experiments available in an accessible way. Bringing the student closer to the spectrophotometric technique, promoting scientific development, and elaborating the hypothesis about using technology as an analysis tool. Conclusions: Experimental practices promote the development of research, which guide both teachers and students in the use of new technologies and in the development of new activities aimed at teaching, this work in question opens a range for the use of tools and methods of easy access and low cost.