Research

MILs are an intriguing class of ionic liquids comprised of magneto-active anions or cations. MILs exhibit paramagnetic behavior under an applied external magnetic field. By exploiting synthetic chemistry, we have succeeded in developing MILs that exhibit low miscibility in water while also retaining sufficient magnetic susceptibility. Currently, we are interested in developing additional classes of MILs that can be used for the selective extraction of analytes in complex environmental and biological samples.

GTIs are compounds that can induce genetic mutations, chromosomal breaks, and/or chromosomal rearrangements in humans. Additionally, these compounds can also exhibit potential carcinogenic activity. The United States Food and Drug Administration (FDA) and the European Medicines Agency (EMA) have imposed stringent regulations on the amount of GTIs present in pharmaceuticals. Depending on the dose and duration of exposure, the allowable daily intake (ADI) can be as low as 1.5 μg/day, which in perspective, would be translated to low parts-per-million (ppm) or sub-ppm concentration ranges of GTIs in drug substances. This highly conservative threshold also applies to pharmaceutical impurities containing structurally alerting functional groups that may possess genotoxic activity. Although GTIs that enter human body may come from drug substances, excipients, degradants, or metabolites, the major source of GTIs is usually active pharmaceutical ingredient (API) manufacturing, which may require the use of genotoxic reagents, solvents, and catalysts. Thus, monitoring the presence of various GTIs in drug substances is of great importance for the pharmaceutical industry.

Solid-phase microextraction (SPME) is a popular sample preparation technique that involves the preconcentration of analytes from a variety of matrices, often without the need for sample pre-treatment. Our group has been focusing on the practical and fundamental aspects of SPME, particularly in the development of highly selective sorbent coatings using polymeric ionic liquids (PILs). The ability to alter the chemical composition of these materials by the means of synthesis or by employing different cation/anion combinations has produced coatings that exhibit superior selectivity for target analyte(s) in various sample matrices.

Multidimensional gas chromatography (MDGC) is an extremely valuable tool for the separation, detection, and identification of volatile and semi-volatile constituents in many complex samples. A typical MDGC separation employs two or more gas chromatographic separations in a sequential fashion. In order to achieve a significant improvement in resolution power, the stationary phases employed often possess different selectivities. Until recently, commercial poly(siloxane)- and poly(ethylene glycol)-based stationary phases have been widely applied in MDGC separations. However, their solvation characteristics and thermal stabilities are often limited for particular classes of compounds, such as those complex mixtures often found in the petrochemical industry.