Surface Plasmon Resonance Spectroscopy of Gold Nanoparticle-Coated Substrates: Use as an Indicator of Exposure to Chemical Warfare Simulants

摘要

Gold nanoparticles with diameters of 9 +or- 6 nm have been synthesized, using the citrate reduction method, and deposited onto quartz substrates. The responsiveness of the resulting gold nanoparticle films to gas- phase warfare agent simulant exposures has been examined using 2-chloroethyl ethyl sulfide and paraoxon. Significant shifts in the peak position of the surface plasmon resonance associated with the nanoparticles were observed in both cases. This shift was reversible and the peak positions returned to their pre-exposure values once the simulants were removed. The response to the exposure events was also found to be faster than (caret)10 s, the rate at which data was acquired in the experiments. A larger shift was observed upon exposure of the films to formaldehyde, a highly hazardous toxic industrial chemical. Unlike 2-chloroethyl ethyl sulfide and paraoxon, the shift was not readily reversible and extensive heating and pumping under vacuum was required to shift the peak position back to pre-exposure values. Through analysis of the 2-chloroethyl ethyl sulfide and paraoxon data, (caret)600 pM and (caret)2 nM are estimated as lower detection limits for the two simulants, respectively.