Using Lego Mindstorms Nxt™ Robotics Kits as a Spectrophotometric Instrument

High-end spectrophotometric analytical instruments are typically employed in academic institutions and industrial research laboratories and are rarely available for experimenters or younger students. An affordable high-tech robotic product manufactured by Lego may be employed as a single-beam monochromatic light source, detector and display to demonstrate and investigate the Beer-Lambert law using solutions containing chromophores that absorb light in the 600 nm - 660 nm range. Using the materials shown in this work, users will gain an understanding of the measurement of optical properties of solutions, and basic properties of semiconductor photonic devices. Some semiconductor theory is essential to understand the photonic devices employed in this work in addition to an understanding of basic analytical chemistry The majority of this work addresses the relationship between concentration and absorbance.