Fiber optic system to measure adulteration in liquids using an RGB detection

• Published in: Suplemento de la Revista Mexicana de Física Vol. 2; no. 1 Jan-Mar; pp. 98 - 102
• Main Authors: Vera-Duarte, O. X., Filoteo-Razo, J. D, Estudillo-Ayala, J. M., Hernandez-Garcia, J. C., Jauregui-Vazquez, D., Sierra-Hernandez, J. M., Martinez-Angulo, J. R., Martin-Vela, J. A., Rojas-Laguna, R.
• Format: Journal Article
• Language: English
• Published: 31.03.2021
• DOI: 10.31349/SuplRevMexFis.2.1.98
• ISSN: 2683-2585

In this paper, we propose a fiber optic system to measure the changes in the RGB composition of light in liquid solutions using a plastic optical fiber (POF) as an intrinsic sensor. The measurement system is composed of a 3 W white light-emitting diode as the light source, a 20 cm long U-shaped POF, and an RGB photodiode array that allows us to detect the changes in the RGB composition of the light propagating through the POF. The U-shaped POF has a length of 5 mm without coating, which remains in contact with the liquid solutions. The tests were performed with different concentrations of a mixture of tequila and water. The results obtained with the RGB photodiode array showed that the system has a resolution of 0.39 % and a color change sensitivity of 0.1, 0.6, and 0.4 8–bits/% of sample for red, green, and blue colors, respectively. These results will allow us to design a low-cost prototype to measure the amount of adulteration in liquids.