A rapid approach to isolating nitro-explosives from imidazolium and pyrrolidinium ionic liquid solutions using solid phase extraction (SPE)

Abstract

Ionic liquids have received considerable attention as ideal green solvents for synthesis and extraction applications. Ionic liquids, because of their unique set of properties such as low volatility, high stability, excellent solvation ability, ionic strength, and tunable structure, are frequently utilized as alternate environmentally friendly solvents to conventional solvents. It is these same properties, however, that present analytical challenges, particularly with liquid chromatography (LC) or gas chromatography (GC) analysis of compounds of interest dissolved in ionic liquid media. A simple solid phase extraction (SPE) sample preparation method is described for isolating nitro-explosive compounds from solutions containing 1,2-dimethyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide (DMPIm-NTf₂) or 1-methyl-3-butylpyrrolidinium bis(trifluoromethylsulfonyl)imide (BMPy-NTf₂) prior to analysis. High recoveries of the compounds of interest are achieved with substantial removal of the ionic liquid, thus avoiding significant interferences and time-consuming and costly instrumental problems.