Resumen de Application of Light Emitting Diodes to Chemical Analysis: Determination of Copper in Water
Juan Daniel Mozo Llamazares, Manuel Galán Vioque, Emilio Roldán González
In this paper a photometer based on a light emitting diode (LED) is described. The apparatus is very simple and easy to build. The light source is a 5-mm LED, which can be replaced in order to select the emission wavelength. A fiber optic is used to conduct light from the LED to the sample. An inexpensive solid-state light-to-voltage optical sensor is used as detector. Using a yellow LED (peak emission = 595 nm), copper(II) in the μg L-1 range can be accurately analyzed. Errors due to the non-monochromatic emission of the LED are also analyzed on the basis of Beer law deviations. For this purpose, emission and absorption bands are modeled by Gaussian curves.
