A fibre-optic oxygen sensor based on contact charge-transfer absorption

✍ Scribed by Ming Fat Choi; Peter Hawkins

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 431 KB
• Volume: 30
• Category: Article
• ISSN: 0925-4005
• DOI: 10.1016/0925-4005(96)80044-x

✦ Synopsis

A fibre-optic oxygen (02) sensor monitoring at a wavelength of 400 nm has been successfully developed for the determination of gaseous 02. Its working principle is based on the contact charge-transfer absorption ofN, N-~methyl-p-toluidine and 02. The response to changes in O2 concentrations is reversible and in good agreement with the Beer-Lambert law. The response and recovery times are 12 and 26 min, respectively. The sensor can detect a wide range of 02 concentrations, ranging from 4.3 to 100% 02. The precision is 1.45% (n = 5) in a gas mixture of 95% 02 in N2 and the limit of detection is 4.3% 02 (3~rb). The sensor is stable with a 0.53% change in sensitivity per hour. There is a 0.25% °<2-1 decrease of the sensitivity of the sensor to 02 in the range 20-34 °C. Water vapour and nitrogen dioxide interfere slightly, whereas hydrogen sulphide and hydrogen chloride have moderate interference on the sensor. However, chlorine and sulphur dioxide seriously interfere with the sensor.