metal binding to polysaccharides.
AREA OF RESEARCH: Thermochemical studies of weakly
bound adducts
METHODS USED: Solution calorimetry, Isothermal
Microcalorimetry, NMR spectroscopy, computer analysis,
molecular mechanics and semiempirical quantum mechanical calculations
MINIMUM EXPERIENCE: two semesters of General Chemistry
PREFERRED EXPERIENCE: Modern Analytical Chemistry, one
semester
Organic Chemistry
STUDENTS: There are usually two or three students
doing
research, in the summer and/or during
the
school year.
|
|
|
| Spring 2007 graduate Amber
Schultz studied metal binding to polysaccharides. |
Spring 2007 graduate Catherine
Polster studied dyes. |
Andrew Loken is also studying dyes. |
Students from this lab have presented their research at the
Chemistry
Department Seminar;
at a Symposium on Undergraduate Research in Math,
Science and Engineering at Argonne National Laboratory;
at a meeting of the Northeastern Wisconsin section
of the American Chemical Society;
at the annual UW Oshkosh Celebration of Scholarship;
and at the UW System Symposium for Undergraduate
Research.
CURRENT PROJECTS:
1.Thermochemistry of heavy metal binding by polysaccharides.
The cyanobacterium Microcystis flos-aquae, which grows in
Lake Winnebago,
produces a polysaccharide capsule that binds heavy metal ions such as
cadmium, copper and lead.
In the long run this material may be useful for cleaning sites
contaminated by toxic metals.
Thermochemical studies let us determine which metals the
polysaccharide binds most strongly.
Measuring the enthalpy (DeltaH) of a reaction gives us the strength of
the bond,
and measuring the equilibrium constant (K) for a reaction tells us the
extent of binding.
We look at the properties of a variety of metal (II) ions as well as
the simple sugar units which make up the polysaccharide
in an attempt to understand why the polysaccharide prefers certain
metals.
The data is primarily generated in calorimetry experiments.
Solution calorimeters are used for saccharide experiments; the
microcalorimeter is for polysaccharide experiments.
Data collection and analysis is done with computers.
related publications:
J. E. Mihalick, W. P. Griffiths III*, J. E. Muten*, T. A. Olson*, J.
B. Hein*, "Thermochemistry of Binding of Lead (II) and Cadmium (II) by
Saccharides in Aqueous Solution." Journal of Solution Chemistry
28, 1025-1036 (1999).
D. L. Parker, J. E. Mihalick, J. L. Plude, M. J. Plude,T. P. Clark*,
L. Egan, J. J. Flom*, L.C. Rai, H.D. Kumar, "Sorption of metals by
extracellular polymers from the cyanobacterium Microcystis
aeruginosa f. flos-aquae strain C3-40." Journal
of
Applied
Phycology 12, 219-224 (2000).
2. Thermochemistry of dye binding by metal
mordants.
People have been dyeing fabrics since prehistoric times. By
trial and error it was discovered
that some metal salts improve the binding of dyes to fabrics, allowing
the color to resist fading
in water or sunlight. The binding agents are called mordants, meaning
"biting."
Spectroscopic and calorimetric experiments provide qualitative
information about the color change,
and quantitative information about the effects of metals on a dye's
binding strength.
related publications:
J. E. Mihalick, K. M. Donnelly. “Using metals to change the
colors of natural dyes.” Journal of
Chemical
Education 83, 1550-1551
(2006).
J. E. Mihalick, K. M. Donnelly. "Cooking up colors from plants,
fabric and metal." Journal of
Chemical
Education 84, 96A
(2007).
go to to Research Opportunities for Chemistry Majors