Amperometric Sensors: Features and Benefits

• Microband electrodes
  • High sensitivity/Low noise measurement of gas concentration
  • Fast Response
  • Tolerant of lower conductivity electrolytes, e.g. SPE
• Solid Polymer Electrolyte (SPE)
  • Long life, leak free
  • Room temperature operation = very low power
• Novel Fabrication Methods
  • Very small size
  • Low cost
  • Multiple sensor elements in a single device

Amperometric Sensors: Operating Principles

• Solid Electrolyte (SPE)
• Exposed microband working electrodes
  • Usually gold, platinum or carbon
• Analyte reaction occurs at working electrode, releasing electrons.
  • e.g. CO + H2O ? CO2 + 2H+ +2e-
• Counter/Reference Electrode supplies electrons and provides constant potential versus working electrode
  • e.g. ½ O2 + 2H+ + 2e- ? H2O

Operation of Amperometric Sensors

• Sensors operate at room temperature and are inherently low power
• Analyte reaction occurs at specific applied voltage
• Sensor output (current) is proportional to gas concentration