Cynthia A. Corley

Single-pot extraction-analysis of dyed wool fibers with ionic liquids.

Analytical capabilities to identify dyes associated with structurally robust wool fibers would critically assist crime-scene and explosion-scene forensics. Nondestructive separation of dyes from wool, removal of contaminants, and dye analysis by MALDI- or ESI-MS, were achieved in a single-pot, ionic liquid-based method. Ionic liquids (ILs) that readily denature the wool α-keratin structure have been identified and are conducive to small volume, high-throughput analysis for accelerated threat-response times. Wool dyed with commercial or natural, plant-based dyes have unique signatures that allow classification and matching of samples and identification of dyestuffs. Wool released 0.005 mg of dye per mg of dyed wool into the IL, allowing for analysis of single-thread sample sizes. The IL + dye mixture promotes sufficient ionization in MALDI-MS: addition of common MALDI matrices does not improve analysis of anionic wool dyes. An inexpensive, commercially available tetrabutylphosponium chloride IL was discovered to be capable of denaturing wool and was determined to be the most effective for this readily fieldable method.

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

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.

Fulleride Based Ionic Liquids

A room temperature fulleride-based ionic liquid has been developed and characterized. Utilizing the trihexyl(tetradecyl) phosphonium cation, the ionic liquid [PC6C6C6C14]3[C60]Cl was synthesized, and distinctly shows spectroscopic characteristics of the [C60] anion. The glass transition of the ionic liquid occurs well below room temperature at -56°C, but it still retains an extremely high viscosity at room temperature. Attempts were made to obtain the pure fulleride salt [PR4]3[C60], but nearly always results in the binary fulleride-chloride salt.