Molecularly imprinted polymer-based electrochemical sensor for the sensitive detection of glyphosate herbicide

Abstract

International audienceA sensitive electrochemical molecularly imprinted sensor was developed for the detection of glyphosate (Gly), by electropolymerisation of p-aminothiophenol-functionalised gold nanoparticles in the presence of Gly as template molecule. The extraction of the template leads to the formation of cavities that are able to specifically recognise and bind Gly through hydrogen bonds between Gly molecules and aniline moieties. The performance of the developed sensor for the detection of Gly was investigated by linear sweep voltammetry using a hexacyanoferrate/hexacyanoferrite solution as redox probe, the electron transfer rate increasing when concentration of Gly increases, due to a p-doping effect. The molecularly imprinted sensor exhibits a broad linear range, between 1 pg/L and 1 mu g/L and a quantification limit of 0.8 pg/L. The selectivity of the proposed sensor was investigated towards the binding of Gly metabolite, aminomethylphosphonic acid, revealing excellent selectivity towards Gly. The developed sensor was successfully applied to detect Gly in tap water samples

Recent Development on the Electrochemical Detection of Selected Pesticides: A Focused Review

“…Glyphosate has been reported to be detected using bare and modified electrodes made of gold [28,[37][38][39][40][41][42][43][44], copper [45][46][47], carbon [48][49][50][51][52][53][54], mercury [55][56][57], and platinum [58,59]. Electrochemical methods, type of electrodes, analytical performance, measurement condition, and sample matrix for glyphosate determination are summarized in Table 1.…”

“…Molecularly imprinted polymer (MIP) is an attractive approach in electrochemistry since it allows to specifically recognize target molecules in preference to other closely related compounds based on shape, size, and functional groups [38]. As a result, gold electrodes modified with a molecularly imprinted polymer were developed for glyphosate detection [28]. The electropolymerisation of p-aminothiophenol-functionalised gold nanoparticles was conducted in the presence of glyphosate template molecules.…”

“…Molecular imprinted polymer (MIP) is one of the techniques that is also being heavily explored. The technique uses the principle of creating a negative imprint of the targeted molecule on the electrode surface to achieve better selectivity and sensitivity [27,28]. Another approach that has recently been gaining attention is to immobilize microorganisms on the electrode surfaces and monitor the interaction between these organisms when they get in contact with the targeted analyte [29,30].…”

Molecularly Imprinted Polymer/Metal Organic Framework Based Chemical Sensors

“…Compared to the MIP, the response currents of the NIP (Not Imprinted Polymer) did not change significantly with the concentration change, demonstrating the succesful formation of imprintig cavities in MIP films. The selectivity of the MIP sensors was also investigated towards the binding of structurally related compounds, proving excellent selectivity [37][38][39][40][41][42]. The observed sensitivities of detection can be classified as: 1,3,5-trinitrotoluene > estradiol > gemcitabine > aflatoxin B1 > tetracyclin > glyphosate; these different sensitivities are due to the different rates of doping, concerning the number of imprinted cavities and the charge transfer rate.…”

“…The template was then extracted from the polymer matrix, resulting in selective recognition sites for the analyte of interest. Several template molecules have been investigated such as estradiol [37], aflatoxin B1 [38], 1,3,5-trinitrotoluene [39], gemcitabine [40], glyphosate [41] and tetracycline [42]. These studies followed several steps for the fabrication of selective recognition cavities for the analytes of interest, which are summarized below: computational design, polymerization and removal of the template molecules.…”