Extraction and determination of trinitrotoluenes and products of their biotransformation in soil samples

Abstract

The separation of a mixture of trinitrotoluenes (TNTs) and their metabolites by reverse phase liquid chromatography using different columns with octadecyl stationary phase is presented. The retention behaviour of a mixture of TNTs and their metabolites was studied under different chromatographic conditions. The mixture of methanol/water was used as a mobile phase in isocratic and gradient modes. The effect of content of organic modifier and temperature of mobile phase has been investigated. Very good RP-HPLC separation of 14 nitroaromatic compounds was obtained using stepped gradient elution. Different properties of extraction procedures for isolation of trinitrotoluenes and their metabolites from soil were tested. Experimental conditions of Soxhlet warm extraction (extractant type, extraction time) suitable for efficient extraction of individual analytes were studied. Recoveries over 80% for all studied compounds and over 90% for almost all (11 compounds) were obtained in short extraction time (1 hour). The formation of precipitate during the Soxhlet extraction was observed and the further treatment of extract was necessary. The amount of precipitate formed from an artificial soil was higher than that from a natural one. THF was found as the best solvent suitable for total dissolution of precipitate.

Keywords:

• explosives
• 2,4,6-TNT
• metabolites
• Soxhlet warm extraction
• soil
• artificial soil

Acknowledgements

This work was supported by the project MSM 0021622412 of Ministry of Education, Youth, and Sports, Czech Republic.