Development of an optical ph measurement system based on colorimetric effect

• Published in: Indonesian Journal of Electrical Engineering and Computer Science
• Main Author: Mustafa P.N.S.M.; Azam A.S.; Sulaiman M.S.; Omar A.F.; Rahman M.F.A.
• Format: Article
• Language: English
• Published: Institute of Advanced Engineering and Science 2021
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85117717214&doi=10.11591%2fijeecs.v24.i2.pp728-735&partnerID=40&md5=27b2a3251f20258c59f94e78eabd0038

This paper proposed an optical pH measurement system developed to measure the changes of pH levels based on colorimetric reactions with phenol red reagent. The optical sensing was achieved through the implementation of a pair of light emitting diode (LED) and photodiode. The detection mechanism was based on different absorbance of light intensity at pH values of 2.36, 8.32, 9.08 and 12.83. The data processing method was carried out using LabVIEW software and interfaced with NI USB DAQ 6008. The measured voltage showed a good correlation in relation to the pH level with R2 equals to 0.9624. This relationship was used as a calibration curve in the final system testing. The final measurement of pH showed a good agreement between the actual and measured values with an error of less than 5%, thus indicating the reliability of the proposed system. © 2021 Institute of Advanced Engineering and Science. All rights reserved.