Detection of theophylline using molecularly imprinted mesoporous silica spheres.

Here, we report a three-dimensional (3D) network molecularly imprinted polymer (MIP) on electrode surface to achieve an efficient and specific detection of theophylline in foodstuffs, using theophylline as the template molecule, mesoporous silica nanospheres (MSNs) as the signal transducer to shuttle electrons, and both phenyltriethoxysilane and pyrrole as functional monomers. The electron microscope images reveal the presence of well-distributed hierarchically MSNs with a pomegranate-like morphology, topped with MIP uniform layer. Electrochemical characterizations were carried out to monitor the properties of the resulting sensing platform based on the MIP/gate effect employing hexacyanoferrate molecules as the electrochemical probe. The data show that due to the high conductivity and electron transfer ability of the prepared theophylline-imprinted membrane, this method exhibits excellent sensitivity and binding affinity with a linear dynamic concentration range in excess of six orders of magnitude and low detection limit (0.66 nM), meeting the requirements of theophylline trace analysis.