An integrated portable Raman sensor with nanofabricated gold bowtie array substrates for energetics detection

Area of Science:

• Analytical Chemistry
• Environmental Science
• Materials Science

Background:

• Energetic compounds like perchlorate (ClO(4)(-)) and trinitrotoluene (TNT) pose environmental and security risks.
• Accurate and rapid detection of these compounds in situ is crucial for environmental monitoring and national security.
• Existing detection methods may lack the portability or sensitivity required for field applications.

Purpose of the Study:

• To develop and evaluate an integrated field-portable Surface-Enhanced Raman Scattering (SERS) sensing system.
• To enable quantitative analysis of energetics, specifically perchlorate (ClO(4)(-)) and trinitrotoluene (TNT).
• To assess the system's performance at environmentally relevant concentrations in real-world samples.

Main Methods:

• Development of a portable Raman spectrometer with an optical fiber probe.
• Utilization of novel elevated gold bowtie nanostructural arrays as a reproducible SERS substrate.
• Application of the standard addition technique for quantitative analysis in groundwater samples.

Main Results:

• Successful quantification of perchlorate (ClO(4)(-)) down to 0.66 mg L(-1) (~6.6 µM).
• Successful quantification of trinitrotoluene (TNT) down to 0.20 mg L(-1) (~0.9 µM).
• Demonstrated detection in groundwater samples from military sites at environmentally relevant conditions.

Conclusions:

• The developed field-portable SERS system provides a sensitive and reproducible method for detecting energetics.
• This technology represents a significant step towards rapid, in situ screening for environmental and security applications.
• The system shows promise for diverse applications including chemical, biological, and environmental detection.