Optical organophosphate/phosphonate sensor based upon gold nanoparticle functionalized quartz.

Area of Science:

• Analytical Chemistry
• Materials Science
• Nanotechnology

Background:

• Organophosphate/phosphonate (OPP) compounds pose significant public safety risks as nerve agents and pesticides.
• Existing detection methods for OPPs can be complex and time-consuming.
• Development of rapid, selective presumptive tests is crucial for public safety.

Purpose of the Study:

• To design and evaluate a class-selective optical sensor for the presumptive detection of organophosphate/phosphonate (OPP) compounds.
• To investigate the use of gold nanoparticles (AuNPs) and plasmon resonance (PR) for OPP detection.
• To establish the sensor's performance characteristics, including sensitivity and selectivity.

Main Methods:

• Fabrication of an optical sensor utilizing gold nanoparticles (AuNPs) immobilized on a planar quartz substrate.
• Modification of AuNPs using zirconium-phosphorous gold chemistry for enhanced binding and detection.
• Monitoring of the plasmon resonance (PR) shift of AuNPs upon exposure to OPP compounds.
• Testing the sensor's response to specific OPP compounds, including methylphosphonic acid (MPA) and diethylchlorophosphate (DECP).

Main Results:

• The developed optical sensor demonstrated a measurable blue shift in plasmon resonance (PR) upon exposure to OPP compounds.
• The sensor successfully detected diethylchlorophosphate (DECP) at concentrations greater than 5x10(-5) M.
• The achieved limit of detection is comparable to other established ultra-violet visible detection techniques.

Conclusions:

• The designed optical sensor shows promise as a class-selective, presumptive test for organophosphate/phosphonate (OPP) compounds.
• The sensor's mechanism relies on monitoring the plasmon resonance shift of gold nanoparticles.
• This approach offers a potentially rapid and sensitive method for OPP detection, contributing to public safety.