Evaluation of a fiber optic sensor for nitrate monitoring during environmental bioremediation

H. Zhao, H. Pedersen

Research output: Contribution to conferencePaperpeer-review


In-situ bioremediation has led to the need for on-line monitoring of nitrate and nitrite ions in contaminated ground water, soil, and sediment. An improved fiber optic chemical sensor is introduced for this purpose. The sensing mechanism employs co-extraction of proton/anion pairs in a basic environment. Investigation emphasized on application of fiber optic technology along with introduction of common non-lipophilized chromoionophores to improve the sensing film loading. Performance comparison was done with various sensing reagents and film matrices; application in monitoring aqueous-phase nitrate and nitrite at pH 7 was carried out. The sensor responds over a concentration range of two decades (from 31 ppm to 3100 ppm for nitrate; from 23 to 2300 ppm for nitrite); it is inert to common interfering ions such as chloride (with a much less response slope). The response time met the requirements for on-line monitoring. Structure design of the sensor is feasible for aqueous phase measurement with strong signal level, little air bubble interference, and easy film installation. Problems encountered in aqueous environment like film swelling and media suspension interference are also addressed.

Original languageEnglish (US)
Number of pages12
StatePublished - 1996
EventProceedings of the 1995 Specialty Conference - San Francisco, CA, USA
Duration: Sep 25 1995Sep 27 1995


OtherProceedings of the 1995 Specialty Conference
CitySan Francisco, CA, USA

All Science Journal Classification (ASJC) codes

  • Environmental Engineering
  • Pollution
  • Waste Management and Disposal


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