New Potentiometric Sensor Based on Molecularly Imprinted Polymer for Dipicolinic Acid Detection in Aqueous Media

A new molecularly imprinted polymer (MIP) was introduced herein for specific detection of dipicolinic acid (DPA) in the complex biological milieu. The MIP was synthesized by precipitation polymerization after a systematic investigation of influential parameters on its adsorption performance. The appropriate functional monomer was selected to be acrylic acid (AA) based on the results of molecular dynamics simulation. The ratio of DPA to AA and to cross-linker was experimentally examined using the full factorial method. The optimal molar ratio of 1:8:24 resulted in the highest adsorption capacity of 47.69 mg g
⁻¹
and imprinting factor of 4.43. The synthesized polymers were characterized by a scanning electron microscopy, a Fourier transform infrared spectroscopy, and an atomic force microscopy. The spherical MIPs possessing a diameter of 483 nm and an imprinting factor of 4.43 was found to play the major role in the development of an efficient MIP-modified carbon paste electrode. This electrode can be cheaply constructed in bulk and be applied for potentiometric DPA sensing in aqueous solutions with a response time and detection limit of 5 min and
$0.1~\mu \text{M}$
, respectively.