2,4,6-Trinitrotoluene detection by laser-photofragmentation-laser-induced fluorescence

Area of Science:

• Analytical Chemistry
• Environmental Science
• Spectroscopy

Background:

• Energetic materials (EMs) require sensitive detection methods in various media.
• Laser-induced fluorescence (LIF) offers a sensitive detection technique.
• Nitric oxide (NO) fluorescence is a key signal in developed methods.

Purpose of the Study:

• To develop and optimize photofragmentation (PF) followed by NO laser-induced fluorescence (LIF) for EM detection.
• To investigate factors influencing PF-LIF signal intensity for accurate EM quantification.
• To establish a detection method for 2,4,6-trinitrotoluene (TNT) in soil.

Main Methods:

• Utilized 226 nm laser radiation for photofragmentation of EMs to NO.
• Employed laser-induced fluorescence (LIF) to detect NO luminescence.
• Studied effects of buffer gas, pressure, temperature, and sample treatment on signal intensity.
• Developed calibration curves for TNT in simulated soil.

Main Results:

• PF-LIF signal intensity is influenced by buffer gas, pressure, and temperature.
• Heating TNT above 343 K significantly increased PF-LIF signal but caused sample changes.
• Achieved a limit of detection of 40 parts in 10(9) for TNT in simulated soil.

Conclusions:

• PF-LIF is a viable technique for measuring EM concentrations in soil.
• Optimization of parameters like temperature and sample handling is crucial for signal enhancement.
• The developed method demonstrates high sensitivity for TNT detection in environmental samples.