个人简介

B.A. University of Utah, 1971, Chemistry Ph.D. Indiana University, 1975, Analytical Chemistry Postdoctoral Research, 1975‑76, Massachusetts Institute of Technology

研究领域

Analytical Chemistry

Fast and accurate chemical analysis methods are required to support current biomedical, pharmaceutical, clinical, environmental, and anti-terrorism activities. The ultimate goal is to develop sophisticated and, in many cases, miniaturized instrumentation that can be used to interrogate a sample with sufficient selectivity, sensitivity, and speed to provide reliable qualitative and quantitative information in near real-time. My research group focuses on the development of new instrumentation and supporting technology in the fields of capillary and micro/nano fluidic separations and mass spectrometry. Research emphasis in past years have included column technology for capillary chromatography and electrophoresis, instrumentation for capillary supercritical fluid chromatography, and instrumentation for time-of-flight mass spectrometry. Current research interests are in monolithic column technology for capillary liquid chromatography and instrumentation for field sampling and hand-portable gas chromatography-mass spectrometry. A monolithic column is a continuous structure in a column or channel with micrometer-size through-pores and nanometer-size pores. Monoliths can be used as stationary phases in liquid chromatography, and media for isolation and concentration of target analytes from mixtures. Monoliths are of interest because of their ease of preparation and enhanced mass transfer characteristics. We have been developing polymer monolithic materials for capillary and microchip liquid chromatography, affinity concentration before capillary electrophoresis, and dispersion reduction in electric field gradient focusing. These monolithic materials have been based on polyethylene glycol-containing acrylate monomers and crosslinkers, which have been found to resist adsorption of peptides and proteins. We are also developing novel hand-portable instrumentation for point detection of chemical warfare agents and environmental chemicals. The detection system is based on the integration of solid phase microextraction sampling, low thermal mass gas chromatography separation, and ion trap mass analysis. The heart of the detection system is a novel toroidal ion trap that increases the trapping volume compared to a conventional ion trap. This allows miniaturization of the ion trap to the size of a US half dollar and minimization of the power requirements such that the trap can be operated using a conventional 12/24 volt military battery. In addition to the development and testing of the novel toroidal ion trap, selective polymer coatings for solid phase microextraction and alternative approaches for high speed gas chromatography are being investigated. Furthermore, we are developing methods for generating volatile biomarkers from biological warfare agents which can be detected using the hand-portable GC-MS system. Additional research areas: Bioanalytical, Environmental, Capillary Chromatography and Electrophoresis, Mass Spectrometry, Microfluidics, Microseparation Techniques, Monolithic Stationary Phases and Hand-portable GC-MS

近期论文

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S. Sharma, A. Plistil, R.S. Simpson, K. Liu, P.B. Farnsworth, S.D. Stearns. M.L. Lee, “Instrumentation for Hand-Portable Liquid Chromatography,” J. Chromatogr. A 1327, 80-89 (2014). P. Aggarwal, V. Asthana, J.S. Lawson, H.D. Tolley, D.R. Wheeler, B.A. Mazzeo, M.L. Lee, “Correlation of Chromatographic Performance with Morphological Features of Organic Polymer Monoliths,” J. Chromatogr. A 1334, 20-29 (2014). P. Aggarwal, J.S. Lawson, H.D. Tolley, M.L. Lee, “High Efficiency Polyethylene Glycol Diacrylate Monoliths for Reversed-phase Capillary Liquid Chromatography of Small Molecules,” J. Chromatogr. A 1364, 96-106 (2014). K. Liu, P. Aggarwal, H.D. Tolley, J.S. Lawson, M.L. Lee, “Fabrication of Highly Cross-linked Reversed-phase Monolithic Columns via Living Radical Polymerization,” J. Chromatogr. A 1367, 90-98 (2014). H.D. Tolley, S.E. Tolley, A. Wang, M.L. Lee, “Moving Thermal Gradients in Gas Chromatography,” J. Chromatogr. A 1374,189-198 (2014). A. Wang, S. Hynynen, A.R. Hawkins, S.E. Tolley, H.D. Tolley, M.L. Lee, “Axial Thermal Gradients in Microchip Gas Chromatography,” J. Chromatogr. A 1374, 216-223 (2014). P. Aggarwal, K. Liu, S. Sharma, J.S. Lawson, H.D. Tolley, M.L. Lee, “Flow Rate Dependent Extra-column Variance from Injection in Capillary Liquid Chromatography,” J. Chromatogr. A (2015). S. Sharma, H.D. Tolley, P.B. Farnsworth, M.L. Lee, “LED-based UV Absorption Detector with Low Detection Limits for Capillary Liquid Chromatography,” Anal. Chem. (2015).