Selective Detection of Nitroexplosives Using Molecular Recognition within Self-Assembled Plasmonic Nanojunctions.

Area of Science:

• Analytical Chemistry
• Materials Science
• Supramolecular Chemistry

Background:

• Surface-enhanced Raman spectroscopy (SERS) offers high sensitivity for chemical detection.
• Reproducibility challenges have limited the practical application of SERS sensors.
• Nitroaromatic compounds, including explosives, require sensitive and selective detection methods.

Purpose of the Study:

• To enhance the reproducibility and sensitivity of SERS sensors for nitroaromatics.
• To investigate the use of cucurbit[7]uril (CB[7]) in a hierarchical aqueous self-assembly approach for SERS.
• To explore the host-guest complexation between CB[7] and 2,4-dinitrotoluene (DNT) for improved sensing.

Main Methods:

• Hierarchical aqueous self-assembly of cucurbit[7]uril (CB[7]) and gold nanoparticles.
• Host-guest complexation studies using experimental and computational techniques.
• Surface-enhanced Raman spectroscopy (SERS) for detecting 2,4-dinitrotoluene (DNT).

Main Results:

• Achieved significant improvement in SERS sensor reproducibility via CB[7]-mediated self-assembly.
• Quantified binding parameters for the CB[7]-DNT host-guest complex for the first time.
• Demonstrated a SERS detection limit of approximately 1 μM for DNT.
• Exhibited selectivity against similar nitroaromatics and tolerance to organic contaminants.

Conclusions:

• The CB[7]-mediated hierarchical self-assembly approach significantly enhances SERS sensor reproducibility for nitroaromatics.
• Supramolecular complexation provides a pathway for sensitive and selective detection of explosive markers.
• This method offers a promising strategy for developing robust and reliable SERS-based detection systems.