The analytical instruments, e.g. spectrophotometers, are
often expensive and complex to operate, hence not suitable for introductory chemistry
experiments. Therefore, it is helpful to build a simple and cheap device for
demonstrating basic principles, functions, and components of the spectrophotometer.
Devising portable and simple colorimeter faces some challenges. The first is
providing a simple light source with a monochromatic light and the second is adopting
a cheap and simple detector. The electronic industry within few past decades
has created a great variety of devices that are of considerable advantages when
applied in chemical instrumentation. These devices could help to overcome the challenges
in devising cheap and simple colorimeters. Light emitting diodes (LEDs)
received a great interest in analytical applications and for use as a light source in
commercial portable absorption devices