Investigation of dye-doped sol-gels for ammonia gas sensing

Alvin Persad, Kwok Fan Chow, Wenqun Wang, Enju Wang, Ann Okafor, Neil Jespersen, Jonathan Mann, Andrew Bruce Bocarsly

Research output: Contribution to journalArticlepeer-review

33 Scopus citations


Sol-gel films doped with fluorescein (FL) and phenol red (PR) dyes were evaluated for their responses to ammonia gas. In a steady state, the sensors respond to the gas-phase ammonia evolved from ammonium hydroxide solutions in the range of 5 × 10-6 to 0.05 M for FL-doped gels, and 10-4 to 1 M for PR-doped gels. The sensors have high selectivity for ammonia against larger amines and moderate selectivity against methyl and ethylamines. The FL-gel exhibits rapid and reproducible response to dry NH3 gas samples of 9-50 ppm, while PR-gel is insensitive to ammonia in this low concentration range. The life-times of the sensors are over a year.

Original languageEnglish (US)
Pages (from-to)359-363
Number of pages5
JournalSensors and Actuators, B: Chemical
Issue number1
StatePublished - Jan 29 2008

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Electrical and Electronic Engineering
  • Materials Chemistry


  • Ammonia gas
  • Fluorescein
  • Optical sensor
  • Sol-gel


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