A swelling-based chemiresistor for a biogenic odour

Area of Science:

• Nanotechnology
• Chemical Sensing
• Environmental Monitoring

Background:

• Escherichia coli (E. coli) metabolism produces 1-decanol, a volatile organic compound.
• Swelling-based sensors offer potential for detecting volatile organic compounds (VOCs).
• Achieving low limits of detection (LOD) for specific VOCs remains a challenge in sensor technology.

Purpose of the Study:

• To develop and characterize a highly sensitive swelling-based sensor for 1-decanol detection.
• To investigate the influence of nanoparticle ligands and odorant properties on sensor performance.
• To explore the sensor's quantitative behavior and response under varying conditions.

Main Methods:

• Fabrication of Langmuir-Schäfer deposited gold (Au) core/organic ligand shell nanoparticle (CSNP) films.
• Detection of 1-decanol odor using resistance change measurements.
• Sensor response evaluation at various partial pressures and temperatures, including near the analyte's freezing point.

Main Results:

• Demonstrated detection of 1-decanol at a partial pressure as low as 100 parts per billion (ppb).
• Achieved an exceptionally low LOD for swelling-based sensors through ligand matching and exploiting low odorant volatility.
• Observed unique quantitative sensor behavior: weak dependence on partial pressure and distinct temperature scaling.

Conclusions:

• The developed Au-CSNP sensor exhibits high sensitivity for 1-decanol detection.
• Sensor performance is significantly influenced by ligand selection and the physicochemical properties of the target odorant.
• Unexpected quantitative behavior suggests complex interactions near the analyte's phase transition, warranting further investigation.