个人简介

B.S., 1971, Duke University M.S., 1974, Emory University Ph.D., 1975, Emory University Postdoctoral Fellow, 1975–1976, University of Houston Distinguished Undergraduate Research Mentor, University of South Carolina, 2007; Sigma Xi Distinguished Lecturer, 2008-2009; American Chemical Society, South Carolina Section, 2011 Outstanding Chemist, May 2011

研究领域

Analytical

Analytical chemistry. Forensic and environmental analysis using chromatography and mass spectrometry; trace evidence analysis of textile fibers and polymers; rapid spectroscopic visualization of biological stains; analytical pyrolysis; chemometrics. I have wide ranging research interests in analytical chemistry and applied statistics, especially in analytical method development using experimental design, optimization, and pattern recognition. Our research has targeted diverse areas including analytical separations (GC, LC, and CE), mass spectrometry, analytical pyrolysis, and spectroscopy (UV/visible, fluorescence, ATR-IR, diffuse reflectance IR, and Raman). Recent research has focused on improvements in forensic fiber analysis, remote detection of biological stains at crime scenes using DRIFTS, and sample preparation methods coupled to GC/MS and LC/MS for pesticides, food adulterants, and drugs of abuse (with Dr. Brewer). Dyes Extracted from Trace Evidence Fibers We are developing and validating forensic analytical methods using microextraction, followed by separations and mass spectrometry, for trace analysis of fiber dyes. Figure 1 shows reconstructed ion electropherograms compared to standards for three dyes extracted from a 2 mm acrylic fiber, with detection limits in the picogram range. Determining the number and relative amounts of dyes present, and characterizing those dyes at the molecular level by MS, offers an entirely new level of forensic trace fiber discrimination. Figure 1. Reconstructed ion electropherograms for dyes extracted from a 2 mm acrylic fiber. Chemometrics We are using multivariate statistics to facilitate visualization of differences and hypothesis testing for decisions based on forensic analytical data. Figure 1 shows linear discriminant analysis for 10 replicate UV/vis spectra from 7 different fibers. Except for fibers 4 and 5, which have similar dye formulations, patterns of all other groups of fibers are discriminated. Spectra from two fibers not dyed with a blue dye (6 and 7) are at the bottom of the plot. The three groups of spectra from fibers dyed with the red 1 dye are on the left side of the plot, and those dyed with the red 2 dye are in the middle region of the plot. Identifying unique features (chromatographic peaks or spectral wavelengths) that distinguish one pattern from another is essential for understanding the chemical basis for differences at a fundamental level. Figure 2. LDA of UV/visible spectra from 7 dyed nylon fibers Forensic Imaging with DRIFTS In collaboration with the Myrick group, we have developed remote imaging techniques for the visualization of biological stains at crime scenes. Detection is based on processed reflectance measurements of characteristic absorption bands in mid-infrared range reflected from surface stains that contain proteins. Figure 3 shows diffuse reflectance spectra for neat and blood-coated acrylic fabric. Spectral differences are seen in regions where IR absorbances due to blood proteins are found (amide I, II, and III peaks at 1200-1650 cm-1; amide A and B at 2800-3500 cm-1). Detection limits are estimated in the range of 200× diluted blood.

近期论文

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Kaewsuya, P.; Brewer, W. E.; Morgan, S. L.; Wong, J. ""Automated QuEChERS Tips for GC/MS Analysis of Fruit and Vegetables,"" J. Agric. Food Chem. 2013, 61, 2299-2314. Myrick, M.L.; Morgan, S. L.. ""Infrared specular reflection calculated for polymer films on polymer substrates: Models for the spectra of coated plastics,"" Spectroscopy, August 2012, 40-56. Myrick, M.L.; Simcock, M.; Baranowski, M. R.; Brooke, H.; Morgan, S. L.; McCutcheon, J. N. ""The Kubelka-Munk diffuse reflectance formula revisited,"" Applied Spectroscopy Reviews, 2011, 46, 140-165. Baranowski, M. R.; Brooke, H.; McCutcheon, J. N.; Morgan, S. L.; Myrick, M. L. ""Coating Effects on Fabric Infrared Reflectance Spectra,"" Applied Spectroscopy, 2011, 65(8), 876-884. Guan, H.; Brewer, W. E.; Garris, S. T.; Morgan, S. L., ""Disposable pipette extraction for enrichment of pesticides from fruits and vegetables and direct analysis by GC/MS,"" J. Chromatogr. A 2010, 1217, 1867-1874. Brooke, H.; Baranowski, M. R.; McCutcheon, J. N.; Morgan, S. L.; Myrick, M. L. ""Multi-mode imaging in the thermal infrared for chemical contrast enhancement. Part 1: Methodology,"" Analytical Chemistry, 2010 82, 8412-8420. Brooke, H.; Baranowski, M. R.; McCutcheon, J. N.; Morgan, S. L.; Myrick, M. L. ""Multi-mode Imaging in the Thermal Infrared for Chemical Contrast Enhancement Part 2: Simulation Driven Design,"" Analytical Chemistry, 2010, 82, 8421-8426. Brooke, H.; Baranowski, M. R.; McCutcheon, J. N.; Morgan, S. L.; Myrick, M. L. ""Multi-mode Imaging in the Thermal Infrared for Chemical Contrast Enhancement Part 3: Visualizing Blood on Fabrics,"" Analytical Chemistry, 2010, 82, 8247-8431. B. L. Vann, S. M. Angel, S. L. Morgan, J. E. Hendrix, E. G. Bartick, ""Analysis of titanium dioxide in synthetic fibers using Raman microspectroscopy"", Applied Spectroscopy 2009, 63(4), 407-411. S. T. Ellison, A. P. Gies, D. M. Hercules, and S. L. Morgan, ""Py-GC/MS and MALDI-TOF/TOF CID study of polyphenylsulfone fragmentation reactions,"" Macromolecules 2009, 42 (15), 5526-5533. A. R. Stefan, C. R. Dockery, A. A. Nieuwland, S. N. Roberson, B. M. Baguley, J. E. Hendrix, S. L. Morgan, ""Forensic analysis of anthraquinone, azo, and metal complex acid dyes from nylon fibers by micro-extraction and capillary electrophoresis,"" Anal. Bioanal. Chem. 2009, 394, 2077-2085.