A simple low-cost UV light photometer for experimental teaching of the Beer-Lambert law
DOI
https://doi.org/10.25267/Rev_Eureka_ensen_divulg_cienc.2024.v21.i3.3401Info
Authors
- Evelyn Toque-Huaman (PE) Peruvian University of Applied Sciences https://orcid.org/0000-0003-0836-3044
- Julio David Gonzales Balladares (PE) universidad de Ingenieria y Tecnlogia https://orcid.org/0000-0002-7379-9875
Abstract
This article presents a low-cost photometer for experimental teaching designed to determine hexavalent chromium in aqueous solutions based on the detection of yellow chromate ions with ultraviolet light at 373 nm. This procedure replaces the colorimetric method that uses a spectrophotometer for the detection of the red-violet 1.5-diphenylcarbazide complex at 540 nm. To demonstrate the operation of the photometer, the Beer-Lambert law was evaluated using the linear regression technique, and the absorbance values obtained by the photometer were compared with those of a Shimadzu UV-2600 series UV-Vis spectrophotometer in five samples of hexavalent chromium in the range of 1 – 25 mg L-1. The experimental results demonstrated the linearity required by the Beer-Lambert law with a determination coefficient of 0.9988, and similarity between both analytical instruments with a relationship of 1.0041 between the absorbance values with a determination coefficient of 0.9993. In conclusion, the low-cost photometer is an excellent proposal for teaching the Beer-Lambert law in the classroom because it reduces the formation of waste, and dispenses with the reagents of the colorimetric method.
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Copyright (c) 2024 Evelyn Toque-Huaman, Julio David Gonzales Balladares
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