Molecularly Imprinted Polypyrrole Based Impedimentric Sensor for Theophylline Determination

• Sensor based on polypyrrole imprinted by theophylline (MIP) deposited on oxygen terminated boron-doped nanocrystalline diamond was developed.
• This structure was applied as impedimetric sensor sensitive for theophylline.
• Optimal polymer formation conditions suitable for MIP formation were elaborated.
• Some analytical parameters were determined and evaluated.

In this study development of impedimetric sensor based on oxygen terminated boron-doped nanocrystalline diamond (B:NCD:O) modified with theophylline imprinted polypyrrole is described. Hydrogen peroxide induced chemical formation of polypyrrole molecularly imprinted by theophylline was applied for the modification of conducting silicon substrate covered by B:NCD:O film. Non-imprinted polypyrrole layer was formed on similar substrate in order to prove efficiency of imprinted polypyrrole. Electrochemical impedance spectroscopy was applied for the evaluation of analyte-induced changes in electrochemical capacitance/resistance. The impact of polymerization duration on the capacitance of impedimetric sensor was estimated. A different impedance behavior was observed at different ratio of polymerized monomer and template molecule in the polymerization media. The influence of ethanol as additive to polymerization media on registered changes in capacitance/resistance was evaluated. Degradation of sensor stored in buffer solution was evaluated.

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