dc.description.abstract |
In this work the development of two molecularly imprinted polymers, specific
for ochratoxin A, is presented. Ochratoxin A is produced by several
Aspergillus and Penicillium species and is common in cereals and other
starch rich foods and has also been found in coffee, dried fruits, wine, beer
and meats. It demonstrates potent teratogenic, immunosuppressive,
mutagenic and carcinogenic properties. The toxin is also linked to Balkan
Endemic Nephropathy, a chronic kidney disease found in South-Eastern
Europe. Due to this the European Union has set limits on foodstuffs ranging
between 2-10 ng g-1. Therefore the requirement of a simple and inexpensive
biosensor to monitor this legislation is a necessity. Currently detection is
performed by chromatographic methods such as HPLC, and by ELISA
formats.
In this work two polymeric materials, rationally designed by computational
modelling and synthesised using molecular imprinting, are studied. The
modelling is complimented with a Nuclear Magnetic Resonance (NMR) study.
The first polymer (Polymer A) consisted of 1 mol of acrylamide and 1 mol of
methacrylic acid to 1 mol of template. This material demonstrated an unusual
binding mechanism, working solely in aqueous solvents. A theoretical
mechanism for this binding is presented and discussed.
The second polymer, again rationally designed, but under different conditions,
consisted of 1 mol of N,N- diethylamino ethyl methacrylate (DEAEM) to 1 mol
of template. This polymer demonstrated high affinity for the template in
acetonitrile.
Polymer A is used in combination with an ion-exchange SPE protocol
(developed for this purpose) for the extraction of OTA from maize.
Both polymer compositions are used in development of a MIP membrane
optical sensor, with partial success seen in the detection of OTA in grape juice
and white wine. |
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