In-line photometer with pSi-based DBR for wavelength-selective transmittance measurement of methylene blue

Authors

Adonis Villagomez ⋅ PH National Institute of Physics, University of the Philippines Diliman
Joybelle Lopez ⋅ PH Materials Science and Engineering Program, University of the Philippines Diliman
Arvin Jay Escolano ⋅ PH Materials Science and Engineering Program, University of the Philippines Diliman
Arven Cafe ⋅ PH Materials Science and Engineering Program, University of the Philippines Diliman
Jeremias Armonia ⋅ PH National Institute of Physics, University of the Philippines Diliman
Ferdinand Cayabyab ⋅ PH National Institute of Physics, University of the Philippines Diliman
Elmer Estacio ⋅ PH National Institute of Physics, University of the Philippines Diliman
Arnel Salvador ⋅ PH National Institute of Physics, University of the Philippines Diliman
Armando Somintac ⋅ PH National Institute of Physics, University of the Philippines Diliman

Abstract

An in-line photometer setup was designed to measure the transmittance and calculate the trace concentration of methylene blue (MB) in water samples. Different concentrations of MB, with a known peak absorbance at λ ~ 660 nm, were prepared. A test MB solution with known concentration was also prepared. UV-Vis spectrophotometry was initially performed to characterize the dye solutions. A porous Silicon-based (pSi) distributed Bragg reflector (DBR), with experimental peak reflectance centered at λ = 665 nm, was integrated into the setup for wavelength-selective purposes. Using the photometer setup, it was found that the proposed setup exhibited high precision in terms of transmittance measurements of the dye solutions due to low standard deviation, σ. The trace concentration of the test solution was calculated and it was found to be in good agreement with the known value with a 2.74 % deviation. The operation range of the setup was set to be from 1 × 10^-⁵ M to 10 ×10^-⁵ M of MB dye solutions because the measurements in these range were linear with more than 95% linearity.

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Issue

2018: Proceedings of the 36th Samahang Pisika ng Pilipinas Physics Conference

Article ID

SPP-2018-PA-37

Section

Poster Session A (Materials Science, Instrumentation, and Photonics)

Published

2018-05-29

How to Cite

[1]

A Villagomez, J Lopez, AJ Escolano, A Cafe, J Armonia, F Cayabyab, E Estacio, A Salvador, and A Somintac, In-line photometer with pSi-based DBR for wavelength-selective transmittance measurement of methylene blue, Proceedings of the Samahang Pisika ng Pilipinas 36, SPP-2018-PA-37 (2018). URL: https://proceedings.spp-online.org/article/view/SPP-2018-PA-37.