A pH sensor constructed with two types of optical fibers: the configuration and the initial results

✍ Scribed by Tianyou Hao; Xuekun Xing; Chung-Chiun Liu

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 391 KB
• Volume: 10
• Category: Article
• ISSN: 0925-4005
• DOI: 10.1016/0925-4005(93)80040-i

✦ Synopsis

A fiber-optic-based pH sensor using phenol red as the indicator is described. This pH sensor employs two different optical fibers, one a hard polymer-cladded silica core and one a fluorinated acrylic-cladded methyl-methacrylate core, and is constructed in a single-path device that increases the signal level and simplifies the signal processing and the replacement of the dye. The sensor performs reasonably well over the pH range 6.040 in terms of the sensitivity and reproducibility. The sensor shows a response time of 2-5 min and can operate for up to seven days with periodic calibrations. The major limiting factor in the sensor's operational life is the deterioration of the membrane and thus the leakage of phenol red from the gel matrix.