A Breath Ammonia Sensor Based on Conducting Polymer Nanojunctions

Alvaro Diaz Aguilar, Erica S. Forzani, N. J. Tao, Larry A. Nagahara, Islamshah Amlani, Raymond Tsui

Research output: Contribution to journalArticlepeer-review

49 Scopus citations


We present an ammonia sensor for human breath analysis based on electrically conducting polymer nanojunctions. Each nanojunction is formed by bridging a pair of gold nanoelectrodes on a silicon chip separated by a small gap (<60 nm) with electrodeposited polyaniline. The signal transduction mechanism of the sensor is the change in the nanojunction conductance as a result of polymer dedoping by ammonia. The sensor response to human breath is validated by comparison with a reference method for detection of ammonium ion combined with an optimized breath ammonia trapping system. The nanojunction sensor is capable of in situ detection of parts per billion (ppb) levels of ammonia in human breath.

Original languageEnglish (US)
Pages (from-to)269-273
Number of pages5
JournalIEEE Sensors Journal
Issue number3
StatePublished - Mar 2008


  • Breath ammonia polyaniline
  • sensor

ASJC Scopus subject areas

  • Instrumentation
  • Electrical and Electronic Engineering


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