Capacitive chemical sensor for fenvalerate assay based on electropolymerized molecularly imprinted polymer as the sensitive layer

Abstract

A capacitive chemical sensor for fenvalerate is reported. By using ac impedance measurements the sensor has been based on the decrease in capacitance caused by the analyte used as the template in the formulation of an electropolymerized molecularly imprinted polymer as receptor layer. Improvement of the insulating properties of the sensor was investigated in detail. The capacitive sensor was prepared by a deposition of a self-assembled monolayer of 2-mercaptobenzimidazole (2-MBI) before electropolymerization of 2-MBI and subsequent treatment with n-dodecanethiol to eliminate pinholes and defects in the polymerized 2-MBI film. From the calibration curve concentrations of fenvalerate up to 9 microg mL(-1) could be detected with a linear determination range up to 5 microg mL(-1) and a detection limit of 0.36 microg mL(-1). No significant interference was observed from common pyrethroid insecticides.

Recognition of Pyrene Using Molecularly Imprinted Electrochemically Deposited Poly(2‐mercaptobenzimidazole) or Poly(resorcinol) on Gold Electrodes

“…printed 2-MBI-coated electrode response to ferricyanide was blocked to a greater degree for pyrene as compared to benzo[a]pyrene which yielded very little response over the same concentration range. The differential response of the template molecule (i.e., pyrene) observed for this electrode was similar to that reported by Gong et al [16] using 2-MBI to form a self assembled monolayer that was electropolymerized in the presence of fenvalerate to form a MIP in which selective electrochemical detection of the template molecule was then shown using impedance spectroscopy.…”

“…The conditions for electrochemical deposition were similar to those reported in the literature [16,17,20], except that the electrode was not preincubated with 2-MBI prior to electropolymerization. In the literature reports, the electrochemical deposition was conducted in alkaline ethanol solution at different pH levels, for example, pH 7.5 [16,17] or 9.5 [20].…”

“…In the literature reports, the electrochemical deposition was conducted in alkaline ethanol solution at different pH levels, for example, pH 7.5 [16,17] or 9.5 [20]. In our experiments, ethanol solution containing 30% (v/v) water was used and the pH was adjusted to 10 using 1 N NaOH in aqueous solution.…”

“…In addition to electropolymerization techniques, the use of self assembled monolayers (SAM) have shown considerable promise in organizing MIPs onto electrode surfaces. Gong et al [16] prepared molecularly imprinted poly(2-mercaptobenzimidazole) (2-MBI) on gold electrodes to detect fenvalerate. Yang et al also used 2-MBI on gold electrodes to detect the herbicide mefenacet [17].…”

Electrochemically synthesized polymers in molecular imprinting for chemical sensing

“…Furthermore, MBI was used as a functional monomer for imprinting of fenvalerate, a synthetic pyrethroid insecticide [189]. For that, the MIP film was deposited on an Au electrode by potentiodynamic electropolymerization in the presence of the fenvalerate template.…”