Improved detection of TNT using SPME-TEEM-GC/MS mode immersion in water and soil.

摘要

The detection of trace amount of explosives is of utmost importance in many day-to-day military operations. The most commonly used explosive in landmines is 2,4,6-trinitrotoluene (TNT). This contribution describes the use of Immersion Mode Solid-Phase Microextraction (I-SPME) for extraction of TNT and their degradation products from surface soil samples for subsequent analysis by either GC/MS and GC with 63Ni micro cell Electron Capture Detector (mu-ECD) and gas chromatograph-mass spectrometer coupled to a Tunable Electron Energy Monochromator (TEEM-GC/MS). A pretreatment step was introduced for the soil samples which extracted the target compounds into an aqueous phase. The experimental results demonstrated the effects of controllable variables. Parameters studied include the chemical properties of the fiber coating, extraction and desorption times, fiber extraction and matrix effect. Surface soil samples containing TNT were evaluated to study the detection of the nitroaromatic explosives and its degradations products. The experimental result demonstrated the relative effects of controllable variables. Using TEEM-GC-MS quantities of TNT as low as 5 pg was detected.