Resumen de Simple and Inexpensive UV-Photometer Using LEDs as Both Light Source and Detector

Eivind V. Kvittingen, Lise Kvittingen, Birte Johanne Sjursnes, Richard Verley

• This article describes how to construct a simple, inexpensive, and flexible UV-photometer using one LED (355 nm) as the light source and another (355 nm) as the detector, one resistor, some wiring, a few Lego bricks, and a millivolt meter. The photometer is used to explore several aspects of molecular absorption spectrometry. As practical applications, the amounts of folic acid in folic acid tablets and cinnamaldehyde in cinnamon were found. The results were in accordance with those obtained using a commercial spectrophotometer.