Colorimetric paper sensor for sensitive detection of explosive nitroaromatics based on Au@Ag nanoparticles

Area of Science:

• Nanotechnology
• Analytical Chemistry
• Environmental Science

Background:

• Effective detection of trace levels of trinitrotoluene (TNT) is critical for homeland security and environmental protection.
• Existing methods for TNT detection may lack the speed, reliability, or onsite capabilities required for immediate threat assessment or environmental monitoring.

Purpose of the Study:

• To develop a novel, rapid, and reliable colorimetric paper sensor for the sensitive and selective detection of trinitrotoluene (TNT).
• To fabricate a nanoprobe based on amine-protected gold-silver nanoparticles (Au@Ag NPs) for onsite, label-free TNT analysis.

Main Methods:

• Fabrication of hydrophilic amine (-NH2) protected Au@Ag nanoparticles (NPs).
• Development of a colorimetric paper sensor utilizing the nanoprobe for TNT detection.
• Investigation of the reaction mechanism involving Meisenheimer complex formation and charge transfer between the amine group and TNT.

Main Results:

• The developed sensor demonstrated selective colorimetric detection of TNT.
• The probe exhibited high selectivity for TNT over other nitroaromatic compounds due to a specific interaction mechanism.
• Achieved a linear detection range of 0-20 μg/mL and a limit of detection (LOD) of 0.35 μg/mL for TNT.

Conclusions:

• The study presents a novel and facile strategy for creating colorimetric paper sensors for TNT detection.
• The developed sensor offers rapid, selective, and sensitive onsite analysis capabilities for trinitrotoluene.
• This approach holds significant potential for applications in homeland security and environmental monitoring.