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

A 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 µg/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.