Solid phase microextraction (SPME) has been coupled with liquid chromatography to widen its range of application to nonvolatile and thermally unstable compounds, generally limited for SPME-GC. A method for analysis of nitroaromatic explosives and its degradations products was developed using SPME and high performance liquid chromatography with ultraviolet detection (HPLC/UV), introducing a modified interface that ensure accuracy, precision, repeatability, high efficiency, unique selectivity and high sensitive to detection and quantification of explosives from surface soil samples and increased chromatographic efficiency. A pretreatment step was introduced for the soil samples which extracted the target compounds into an aqueous phase. Several parameters that affect the microextraction were evaluated, such as: fiber coating, adsorption and desorption time, desorption mode, stirring rate, the effect of NaCl (salting out) concentration on analyte extraction and the role of various solvents on SPME fiber. Carbowax-templated resin (CW/TPR) and Polydimethilsiloxane-divinilbenzene (PDMS-DVB) fibers were used to extract the analytes from the aqueous samples. Explosives were detected at 330 pg concentrations. Effects of daylight and UV radiation were analyzed over soil samples during 1 month and degradations products found were: 1,3,5-TNB, 1,3-DNB, 2,4-DNT, 2,6-DNT, 4-Nitrotoluene and 3-Nitrotoluene. This study demonstrates that SPME-HPLC is a very promising method of analysis of explosives from soils and aqueous samples and has been successfully applied to the determination of nitroaromatic compounds, such as TNT.

Keywords: SPME, HPLC-UV, nitroexplosives, absorption fibers, TNT