NIU Department of
Chemistry & Biochemistry
Where the study of matter...matters!
Associate Dean for Undergraduate Affairs, College of Liberal Arts and Sciences
Recipient of Excellence in Undergraduate Teaching Award
Office: La Tourette Hall 424
Phone: (815) 753-6857
Senior Scientist/Group Supervisor, Geo-Centers, Inc. at the Naval Research Laboratory, 1984-1989
Ph.D., University of Maryland, College Park, 1983
B.S., College of William and Mary, 1977
Materials characterization; solubility properties; viscoelastic properties of polymers; development of gas chromatography methods; chemical microsensors.
Quantitation of phenol levels in oil of wintergreen using gas chromatography/mass spectrometry with selected ion monitoring: A quantitative analysis laboratory experiment. Sobel, R. S.; Ballantine, D. S.; Ryzhov, V. (2005) J. Chem. Educ., 82: 601–603.
Characterization of phosphorus-containing gas chromatographic stationary phases by linear solvation energy relationships. Graffis, C. A.; Ballantine, D. S. (2002) J. Chromatogr. A, 946: 185-196.
Characterization of amine functionalized stationary phases using linear solvation energy relationships. McCann, M.; Ballantine, D. S. (1999) J. Chromatogr. A, 837: 171-185.
Development and application of an automated GC sampling system for verification of test vapor stream concentrations for chemical sensor studies. Torkelson, T.; Ballantine, D. S. (1998) Analyst, 123: 209-215.
Characterization of cyano-funcitonalized stationary GC phases by linear solvation energy relationships. Tian, W.; Ballantine, D. S. (1995) J. Chromatogr., 718: 357-369.
Optical waveguide vapor sensor. U.S. Patent 5,315,673, May 24, 1994. Stetter, J. R.; Maclay, G. J.; Ballantine, D. S., Jr.
Investigation of relative humidity effects on the response behavior of a pH indicator-based OWG vapor sensor. Callahan, D.; Ballantine, D. S. (1993) Talanta, 40: 431-444.
QSRR approach to prediction of LSER coefficients I. H-bond acceptor capability of GC stationary phases in McReynold's data set. Ballantine, D. S. (1993) J. Chromatogr., 628: 247-259.
The primary focus of our research involves the characterization of material properties, particularly solubility properties, and the correlation of these properties with molecular structure. The ultimate goal of these projects is to develop structural descriptors which will permit us to predict solubility properties of materials, and/or aid in the rational design of materials having suitable properties for specific applications.
The tools we use in these characterization studies include gas chromatography and surface acoustic wave (SAW) chemical microsensors. Since the retention of solutes in chromatography is a function of fundamental solubility interactions, we can use retention data obtained from inverse gas chromatography studies in linear solvation energy relationships (LSER) to obtain parameters that quantify the relative ability of stationary- phase materials to engage in specific interactions. The LSER used in our studies is the following, in which each term in the linear equation represents complementary solubility properties of the solutes (designated by subscript 2) and the solvent or stationary phase (designated by subscript 1):
These solubility parameters can then be correlated with molecular structural descriptors to develop quantitative structure solubility relationships (QSSR). In related studies, the viscoelastic properties of polymers can be examined by taking advantage of the unique sensitivity of the SAW microsensors. The response behavior of these devices involves both a mass loading component (i.e., partitioning of a solute vapor into the coating, which can be predicted from GC data) and a viscoelastic component, related to changes in the polymer rigidity modulus. This viscoelastic response can then be correlated with structural features and/or solubility parameters for the vapor/polymer system. Such correlations may provide insight into viscoelastic phenomena, including plasticization, and aid in the development of new materials for use in chemical sensor applications.
Schematic of a coated SAW device and circuit.