Comparison of different methodologies for integration of molecularly imprinted polymer and electrochemical transducer in order to develop a paraoxon voltammetric sensor

In this work a paraoxon voltammetric sensor was introduced. Different methods for integration of molecularly imprinted polymer (MIP) and electrochemical transducer were investigated. Three techniques including MIP particles embedding in the carbon paste (CP) (MIP-CP), coupling of MIP with the glassy carbon electrode (GC) surface by using poly epychloro hydrine (PECH) (MIP/PECH-GC) and MIP/graphite mixture thin layer attachment onto the glassy carbon electrode (MIP/Graphite-PECH-GC) were tested. The prepared electrodes were applied for paraoxon measurement by using a three-step procedure including analyte extraction in the electrode, electrode washing and electrochemical measurement of paraoxon. The washing of electrodes, after paraoxon extraction, led to high selectivity of electrode for paraoxon. It was found that MIP-CP electrode had higher response to paraoxon in comparison to other tested electrodes. Besides, the washing process decreased response magnitude of MIP/PECH-GC and MIP/Graphite-PECH-GC but, the response of MIP-CP was not affected considerably by the washing. Parathion was chosen to evaluate the selectivity of MIP based sensors. It was proved that the MIP-CP had better selectivity, wider linear range and lower detection limit in comparison to other tested electrodes. The developed MIP-CP electrode was used as a high selective sensor for paraoxon determination in water and vegetable samples.