An LED-based multi-sample absorbance spectrophotometer for chemistry and biochemistry.

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Instrumentation

Background:

• Solute concentration determination is crucial in various scientific fields.
• Traditional spectrophotometers can be expensive and complex.
• Need for accessible and cost-effective instrumentation for educational purposes.

Purpose of the Study:

• To develop a low-cost, modular spectrophotometer for measuring visible light absorbance.
• To design an instrument suitable for undergraduate laboratory experiments and field studies.
• To enable students to assemble and understand spectrophotometer construction.

Main Methods:

• Utilized interchangeable light-emitting diodes (LEDs) as cost-effective light sources.
• Employed a photodiode detector and Arduino microprocessor for signal processing.
• Incorporated a modular design for easy assembly and disassembly.
• Integrated an LCD panel for display and USB interface for data transfer.

Main Results:

• The instrument accurately measures absorbance of visible light (400-650 nm) in liquid samples.
• Demonstrated suitability for parallel kinetic experiments with up to six samples.
• Achieved low power consumption (0.4 W from 5 V USB), enabling field use.
• Modular construction facilitates student assembly and learning.

Conclusions:

• The developed spectrophotometer offers a cost-effective and practical solution for solute concentration analysis.
• Its features make it highly valuable for undergraduate teaching laboratories and portable applications.
• The instrument empowers students with hands-on experience in building and utilizing analytical equipment.