Optical organophosphate/phosphonate sensor based upon gold nanoparticle functionalized quartz

Organophosphate/phosphonate (OPP) compounds represent a serious concern to public safety as nerve agents and pesticides. This study discusses the design and use of a class-selective optical sensor which may be used as a presumptive test for OPP presence. This sensor is based upon monitoring of the plasmon resonance (PR) of gold nanoparticles (AuNPs) attached to a planar quartz substrate. Following binding the AuNPs are modified using established zirconium-phosphorous gold modification chemistry. The development of the sensor, including the determination of the appropriate quartz-AuNP linking chemistry will be discussed. These sensors were found to exhibit a blue shift in the PR upon exposure to the OPP compounds methylphosphonic acid (MPA) and diethylchlorophosphate (DECP). It was found that the sensor was able to detect DECP at concentrations greater than 5 × 10−5 M, a value similar to limits of detection reported for other techniques using ultra-violet visible detection.