Characterization of factors influencing absorbance measurements in LED-based colorimeters
Issued Date
2023-03-01
Resource Type
ISSN
01430807
eISSN
13616404
Scopus ID
2-s2.0-85147996541
Journal Title
European Journal of Physics
Volume
44
Issue
2
Rights Holder(s)
SCOPUS
Bibliographic Citation
European Journal of Physics Vol.44 No.2 (2023)
Suggested Citation
Dangkulwanich M., Thitaparun P., Yimkosol W., Chalermsongsak T. Characterization of factors influencing absorbance measurements in LED-based colorimeters. European Journal of Physics Vol.44 No.2 (2023). doi:10.1088/1361-6404/acb46e Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/82243
Title
Characterization of factors influencing absorbance measurements in LED-based colorimeters
Author's Affiliation
Other Contributor(s)
Abstract
Homemade colorimeters using simple parts are excellent in undergraduate teaching labs as they allow students to learn instrument components and principles behind absorbance measurements. However, the absorbance values measured from such instruments often differ from those determined by commercial spectrophotometers. This work provides a step-by-step calculation of absorbance, taking into account the properties of each component. Using a Si-photodiode detector and a light-dependent resistor, we show how the absorbance measurements depend on the spectral irradiance of the light source, the absorption spectrum of the sample, and the responsivity of the detectors. The provided calculation can help undergraduate students visualize how these factors contribute to optical measurements. It can serve as an experiment to introduce concepts of instrumentation and analysis of its performance.