Abstract
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 language | English (US) |
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Pages (from-to) | 359-363 |
Number of pages | 5 |
Journal | Sensors and Actuators, B: Chemical |
Volume | 129 |
Issue number | 1 |
DOIs | |
State | Published - 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
Keywords
- Ammonia gas
- Fluorescein
- Optical sensor
- Sol-gel