Abstract:
This thesis presents broadly the applications of molecularly imprinted polymers in
sensors and solid phase extraction. Sensors for creatine and creatinine have been
reported using a novel method of rational design of molecularly imprinted polymers
(MIPs), and solid phase extraction of aflatoxin-B 1 has also been described in the
thesis.
A method for the selective detection of creataine and creatinine is reported in this
thesis, which is based on the reaction between polymerised hemithioacetal, formed by
allyl mercaptan, o-phthalic aldehyde, and primary amine leading to the formation of
fluorescent isoindole complex. This method was demonstrated for the detection of
creatine using creatine-imprinted MIPs. Since MIPs created using traditional methods
were unable to differentiate between creatine and creatinine, a new approach to the
rational design of a MIP selective for creatinine was developed using computer
simulation. A virtual library of functional monomers was assigned and screened
against the target molecule, creatinine, using molecular modeling software. The
monomers giving the highest binding score were further tested using simulated
annealing in order to mimic the complexation of the functional monomers with
template in the monomer mixture. The result of this simulation gave an optimised
MIP composition. The computationally designed polymer demonstrated superior
selectivity in comparison to the polymer prepared using traditional approach, a
detection limit of 25 μM and good stability. The 'Bite-and- Switch' approach
combined with molecular imprinting can be used for the design of assays and sensors,
selective for amino containing substances.
MEP for the selective binding properties for aflatoxin-B 1 was prepared using the
computational approach. The results obtained demonstrate that the MISPE offers a
simple, convenient and a rapid methodology for solid phase extraction of aflatoxin-B 1
even at very low concentrations of 2 ppb. The commercially available C-18 cartridges
were able to recover only about 52% of aflatoxin-B 1 at concentrations of 2 ppb when
compared with almost complete recovery by the MIP. We have proved here that,
MIPs as a solid phase extraction materials offer important and practical advantages
with respect to other solid phase extraction methodologies.
