Introducing spectrophotometry in the school lab employing LEGO bricks and LEDs

Abstract

In this paper we present the simple process of manufacturing a spectrophotometer based on an assembly of LEGO bricks and LED lights. The procedure is simple and the cost is extremely low. Spectrophotometer’s capabilities were tested employing two analytical chemistry problems as a reference. In the first one we investigated the concentration of a blue food dye in an isotonic beverage. The results obtained are compared with those of a commercially available instrument. In the second one we searched for the concentration of two dyes present in a shampoo. The results suggest that simple DIY spectrophotometers can replace the need of purchasing expensive analytical instruments, at least for the secondary school level.

Keywords

• analytical chemistry
• food dyes
• hands-on activities
• spectrophotometry