Threshold-Responsive Colorimetric Sensing System for the Continuous Monitoring of Gases

Manni Mo, Bo Fu, Piyush Hota, Pinar Cay-Durgun, Ran Wang, Edward H. Cheng, Peter Wiktor, Francis Tsow, Leslie Thomas, Mary Laura Lind, Erica Forzani

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Colorimetric sensors are widely used because of their inherent advantages including accuracy, rapid response, ease-of-use, and low costs; however, they usually lack reusability, which precludes the continuous use of a single sensor. We have developed a threshold-responsive colorimetric system that enables repeated analyte measurements by a single colorimetric sensor. The threshold responsive algorithm automatically adjusts the sensor exposure time to the analyte and measurement frequency according to the sensor response. The system registers the colorimetric sensor signal change rate, prevents the colorimetric sensor from reaching saturation, and allows the sensor to fully regenerate before the next measurement is started. The system also addresses issues common to colorimetric sensors, including the response time and range of detection. We demonstrate the benefits and feasibility of this novel system, using colorimetric sensors for ammonia and carbon dioxide gases for continuous monitoring of up to (at least) 60 detection cycles without signs of analytical performance degradation of the sensors.

Original languageEnglish (US)
Article number3496
Issue number7
StatePublished - Apr 2023


  • artificial intelligence
  • automated sampling
  • colorimetric sensing
  • continuous sensing
  • internal diffusion
  • sensor saturation
  • tunable response

ASJC Scopus subject areas

  • Analytical Chemistry
  • Information Systems
  • Instrumentation
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering
  • Biochemistry


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