Prototype of a modular spectrophotometer for chemistry education

Abstract

Abstract: The article presents a prototype designed for higher education, this prototype is a modular spectrophotometer, which consists of three modules, the first module is the light source, the second module is the cuvette holder in which the electronic transitions occur and in the third module the electronic transitions that occur in the second module are converted into numerical data. This prototype has the advantage of being mobile, it does not become out of calibration, because it uses a set of light emitting diodes (LEDs) as a light source. This prototype measures impedances of a photoresistor, which is affected by the electronic transitions occurring in the second module. This modular spectrophotometer prototype allows us to use it for analytical chemistry by correlating the concentrations of a sample with the impedance of the photoresistor, which is measured with a multimeter. This prototype presents determination coefficients of 0.9993, 0.9990, 0.9989 and 0.9961, respectively for solutions of copper sulfate, potassium permanganate, egg yellow pigment and collagen, these measurements allow us to apply Lambert-Beer law for spectrophotometry.