Molecularly Imprinted Sol-Gel for TNT Detection with Optical Micro-Ring Resonator Sensor Chips

Area of Science:

• Chemical Sensors
• Materials Science
• Analytical Chemistry

Background:

• Developing sensitive and selective detection methods for explosives like trinitrotoluene (TNT) is crucial for security applications.
• Optical micro-ring resonator technology offers potential for miniaturized and high-performance chemical sensors.
• Molecularly imprinted polymers (MIPs) provide a robust platform for creating selective recognition layers for target analytes.

Purpose of the Study:

• To develop a novel sensor for the detection of trinitrotoluene (TNT) in the gas phase.
• To compare different deposition techniques for the molecularly imprinted sol-gel receptor layers.
• To evaluate the sensor's sensitivity, selectivity, and response time for TNT detection.

Main Methods:

• Fabrication of an optical micro-ring resonator sensor.
• Development of molecularly imprinted sol-gel layers as receptor coatings.
• Comparison of airbrush technology and electrospray ionization for receptor layer deposition.
• Gas-phase detection of TNT and other nitro-based explosives and organic substances.

Main Results:

• A detection limit of less than 5 parts per billion (ppb) for TNT was achieved using electrospray deposition.
• The sensor demonstrated high selectivity for TNT, with sensitivity orders of magnitude higher than DNT, DNB, phenol, ethanol, and acetone.
• Fast signal response and a compact sensor design enabling multi-analyte detection on a single chip were observed.

Conclusions:

• The developed optical micro-ring sensor with molecularly imprinted sol-gel layers is a promising technology for sensitive and selective TNT detection.
• Electrospray deposition is an effective technique for creating high-performance receptor layers for explosive sensing.
• The sensor's design facilitates precise analysis and minimizes false alarms, making it suitable for security applications.