Journal of Sensor Science and Technology (센서학회지)

The Korean Sensors Society (한국센서학회)
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Study on Optical Characteristics of pH Indicators in the Immobilized Film for Fiber-Optic pH Sensor

광학적 pH 센서를 위한 지시염료가 고정된 필름의 광학적 특성 연구

  • Kim, Beom Kyu (Department of Energy & Environmental Engineering, Soonchunhyang University) ;
  • Park, Byung Gi (Department of Energy & Environmental Engineering, Soonchunhyang University)
  • 김범규 (순천향대학교에너지환경공학과) ;
  • 박병기 (순천향대학교에너지환경공학과)
  • Received : 2017.10.10
  • Accepted : 2017.11.26
  • Published : 2017.11.30
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Abstract

The optical characteristics of cresol red, phenol red, and neutral red immobilized in the thin film were investigated with absorbance measurement in order to find a sensing part of a fiber-optic pH sensor. Sol-Gel method with tetramethyl orthosilicate as a precursor was used to immobilize the pH indicators in the thin film. The absorbance spectra were measured when pH indicators were immobilized in the film and were dissolved in the buffer solution. Experimental results showed that the absorbance spectra could be changed when the pH indicator is immobilized in the thin film. As compared with other pH indicators, the neutral red exhibited similar absorbance spectra regardless of physical conditions and was sensitive over whole pH range between 4 and 11. In addition, the absorbance ratio of base peak to acid peak tended to increase in proportion to the increase in pH. Experimental results indicate that the neutral red is a good pH indicator for fabrication of a sensing part of the fiber-optic pH sensor.

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References

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