Demonstrating Basic Properties of Spectroscopy Using a Self-Constructed Combined Fluorimeter and UV-Photometer

Abstract

This article describes a combined UV-photometer and fluorimeter constructed from 3 LEDs and a few wires, all held in place with Lego bricks. The instrument has a flexible design. In its simplest version, two UV-LEDs (355 nm) are used as light source and to detect absorption, and a third LED, in the visible spectrum (e.g., 525 nm), is used to detect fluorescence. Various experiments are described: fluorescence as a function of concentration and light source intensity; quantitative measurements of quinine in tonic water, using absorption and fluorescence measurements, with results in line with those obtained on scientific instruments; a demonstration of the inner filter effect reducing fluorescence at higher concentrations; investigation of the effect of drinking tonic water on the fluorescence of quinine in urine; temperature effects on fluorescence; chloride-ion quenching of fluorescence with result comparable to those previously reported; and, finally, a demonstration of phosphorescence.

Practical science at home in a pandemic world

“…Next, the box contains a multimeter, a battery pack, a set of LEDs and some LEGO. Several teachers of chemistry have used these to build colorimeter/fluorimeters 6 . With a LEGO 'spectrometer' Beer-Lambert studies can be developed.…”

Teaching chemistry with LEGO® bricks

“…Several groups have developed hands-on activities with handmade instruments, utilizing LEGO bricks to aid students in understanding the fundamental concepts of various analytical instruments (Albert, Tobt, & Davis, 2012;Bouza, Nastou, Panigyraki, & Makedonas, 2019). Kvittingen and coworkers reported the designs of the following analytical instruments from a combination of LEGO bricks and LEDs for chemical education: a visible photometer (Kvittingen, Kvittingen, Sjursnes, & Verley, 2016), colorimeter (Asheim, Kvittingen, Kvittingen, & Verley, 2014), and a phosphorescent analyzer (Kvittingen, Kvittingen, Melø, Sjursnes, & Verley, 2017). Referring to Kvittingen's reports, the author built three LEGO-based instruments (Figure 20).…”

Demonstrating Basic Properties and Application of Polarimetry Using a Self-Constructed Polarimeter

“… 10 , 11 We have previously published descriptions of simple instruments constructed with plastic interlocking toy bricks, such as Lego, and LEDs for UV–vis absorption and fluorescence measurements intended for student experiments. 12 − 14 We add here polarimetry, extending the range of spectroscopic methods possible with the same basic building blocks. The polarimeter has the same layout as a classical polarimeter, making it easy to explain fundamental principles and instrumental design.…”