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Ryan E. Sours

Associate Professor
Analytical Chemistry

Office: 567 Smith
Phone: (410)704-2669


Education B.S. Chemistry (1998) University of Buffalo, magna cum laude
Ph.D. Chemistry (2004) Georgetown University, with Distinction
Postdoctoral Associate (2004-2006) University of Washington
Teaching General Chemistry I (131)
General Chemistry I Lab (131L)
Introduction to Analytical Chemistry (210)
Instrumentation in Analytical Chemistry (310)
Research My research group is interested in the mechanisms by which trace solution impurities modify the growth of crystals, particularly biominerals. We are currently using HPLC to investigate impurity-crystal interaction kinetics.

During a chromatographic separation, the retention time for a molecule is determined by the relative amount of time spent adsorbed onto the stationary phase. During crystal growth, the extent of growth modification caused by an impurity is likely related to the lifetime of that impurity on the crystal surface. Thus, if biomineral crystals are used as the chromatographic stationary phase, the relative retention time for an impurity molecule should correlate with its effectiveness as a growth modifier for that particular crystal. Molecules with longer retention times (longer surface lifetimes) should be better growth modifiers than those with short retention times.

Our efforts are currently focused on various known and model growth inhibitors for calcite (calcium carbonate) and whewellite (calcium oxalate monohydrate) crystals. Based on relative retention times, peak shapes, and modeling calculations, adsorption kinetics for the impurities are being determined and compared to previously measured efficacies for crystal growth modification.
Selected Publications
  1. Alexander Shtukenberg, Erica Gunn, Massimo Gazzano, John Freudenthal, Eric Camp, Ryan Sours, Elena Rosseeva, and Bart Kahr, “Bernauer’s Bands” ChemPhysChem 2011, 12, 1558-1571. Link to Full Article
  2. Randall C. Mazzarino*, Tissa J. Thomas*, and Ryan E. Sours, “Chromatographic Determination of Impurity Binding Affinities on Biomineral Crystals” CrystEngComm 2011, 13, 1096-1102. Link to Full Article
  3. Amanuel Z. Zellelow, Kristin A. Cox, Dorothy A. Fink, Catherine E. Ford, Kun-Hae Kim, Ryan E. Sours, and Jennifer A. Swift, “Doping Uric Acid Crystals. 2. Anhydrous Uric Acid” Cryst. Growth Des. 2010, 10, 3348-3354. Link to Full Article
  4. Amanuel Z. Zellelow, Melat Abiye, Dorothy A. Fink, Catherine E. Ford, Kun-Hae Kim, Ryan E. Sours, Clare M. Yannette, and Jennifer A. Swift, “Doping Uric Acid Crystals. 1. Uric Acid Dihydrate” Cryst. Growth Des. 2010, 10, 3340-3347. Link to Full Article
  5. Amanuel Z. Zellelow, Kun-Hae Kim, Ryan E. Sours, and Jennifer A. Swift, “Solid-State Dehydration of Uric Acid Dihydrate” Cryst. Growth Des. 2010, 10, 418-425. Link to Full Article
  6. Werner Kaminsky, Erica Gunn, Ryan Sours, Bart Kahr “Simultaneous False-Color Imaging of Birefringence, Extinction, and Transmittance at Camera Speed” J. Microsc. 2007, 228, 153-164. Link to Full Article
  7. Erica Gunn, Ryan Sours, Jason B. Benedict, Werner Kaminsky, Bart Kahr “Mesoscale Chiroptics of Rhythmic Precipitates” J. Am. Chem. Soc. 2006, 128, 14234-14235. Link to Full Article
  8. Ryan E. Sours, Amanuel Z. Zellelow, Jennifer A. Swift “An in Situ Atomic Force Microscopy Study of Uric Acid Crystal Growth” J. Phys. Chem. B 2005, 109, 9989-9995. Link to Full Article
  9. Dorothy A. Fink, Ryan E. Sours, Jennifer A. Swift “Modulated Uric Acid Crystal Growth in the Presence of Acridine Dyes” Chem. Mater. 2003, 15, 2718-2723. Link to Full Article
  10. Ryan E. Sours, Dorothy A. Fink, Jennifer A. Swift “Dyeing Uric Acid Crystals with Methylene Blue” J. Am. Chem. Soc. 2002, 124, 8630-8636. Link to Full Article

Faculty & Staff

Department of Chemistry
Smith Hall 543
Towson University
8000 York Road
Towson, MD 21252