SEPARATION STRATEGIES FOR THE DETERMINATION OF RESIDUES OF EXPLOSIVES IN SOILS USING MICELLAR ELECTROKINETIC CAPILLARY CHROMATOGRAPHY

Micellar electrokinetic capillary chromatography (MEKC) separation strategies for the determination of residues of explosives in soils are presented. Compared to former publications, the number of explosives determined was increased up to 24 compounds in which all EPA priority substances are included. Separation characteristics were investigated as a function of different organic modifiers. Using 1 vol% of methanol, separation was realized for all 24 compounds, including all of the isomers of the mono-and dinitrotoluenes. Furthermore, the lipophilic and hydrophilic parts of the surfactant were varied, and the best separation characteristics were obtained with sodium dodecyl sulphate (SDS). Even the suitability of mixed micelles for the analysis of nitroaromatics was tested. With the help of mixed micelles consisting of SDS and the amphoteric surfactant SB 12, separation of 22 out of 24 explosives was realized. With significantly changed selectivities, complete separation required less than 12 minutes.