Development Of High Sensitive And Reversible Potentiometric Sensors Based On Molecularly Imprinted Polymers

In recent years,polymeric membrane ISE have found vast applications in diverse fields of analysis.Ease of use and simplicity ha ve replaced for long other wet analytical methods,Because they have the advantages of high accuracy,rapid detection,low cost,and strong sensitivity over a wide range of concentrations.Molecular imprintied polymers?MIPs?is recognized as the most promising methodology for the preparation of synthetic tailor-made polymers with selective adsorption.Besides their antibody-like molecular selectivity,MIPs have several other attractive features including robustness,stability at elevated temperatures and pressures,resistance to many chemical environments,use in both aqueous and non-aqueous media,low preparation cost,good shelf-lives and re-use without significant deterioration to their properties.In addition,MIPs are able to bind a variety of target hosts and thus have been used in many different fields.Potentiometric sensors form one of the most important groups of electrochemical transducers and are one of the lowest cost analytical devices available today.The integration of MIP materials in electrochemical sensors has the advantages of high selectivity,ease of miniaturization and automation.In addition,they do not require the analyte to pass through the electrode membranes for detection membrane potentials.However,MIPs membrane ion-selective electrodes still have the disadvantages of higher detection limits and non-reusability.In this work,a series of high sensitive and reversible potentiometric sensors based on molecularly imprinted polymers were developed.?1?Fabrication of a high sensitive potentiometric sensors:All solid contact screen-printed potentiometric sensors have been used and characterized.An electrochemically reduced graphene oxide film was used as the solid contact.The sensing membrane is based on the use of synthesizied MIP nano-beads as the selective receptor.These membrane sensors were usually conditioned with a highly discriminated ion to eliminate the influence of the filling solution on the detection limit of the electrode.The sensors revealed a detection limit of 6.9×10^-11 mol/L.?2?Development of a fully reversible molecularly imprinted based potentiometric sensor:Compared with traditional electrodes after each measurement,the membrane electrode was washed with a mixture of ethanol or ethanol..This not only makes the electrode update step complicated,but also leads to poor electrode stability and reduced lifetime.This study uses bisphenol A molecularly imprinted polymer carriers containing many carboxyl groups as research objects.The polymer membranes were reused by sequentially immersing the polymer membranes with pH 2.0 acid solution and pH 12 alkali solution and achieve the update of molecularly imprinted polymer?3?Design of the miniaturized potentiometric sensing system:In order to overcome the shortcomings of conventional potentiometric sensor that cannot be monitored on site due to their large size.In this experiment,a miniaturized ion meter was designed.This instrument is small,does not require an external power supply and easy to carry,therefore,it can realize the on-site inspection of the sample.This ion meter uses a two-system screen-printed electrode as working electrode and reference electrode to further reduce the detection system.