Gold nanoelectrode arrays dewetted onto graphene paper for selective and direct electrochemical determination of glyphosate in drinking water
Antonino Scandurra, Maria Censabella, Antonino Gulino, Maria Grazia Grimaldi, F. Ruffino
Abstract
Many anthropic activities as dumping of industrial waste, disposal of sewage, pesticides used in agricultural, etc. are key sources of environmental, namely of soil and water, contamination. Therefore, rapid determination of major and minor contaminants is nowadays an important issue for both analytical and remediation purposes. In this context, a large use of glyphosate, suited to kill weeds that compete with crops, has been done. Unfortunately, glyphosate toxicity and carcinogenicity was recently demonstrated. Therefore, it is now urgent to find appropriate methods for the glyphosate determination at very low concentration levels, in order to move on the successive ambient remediation. Some different glyphosate sensors have already been reported, including some electrochemical approaches, but seldom they allow its determination at the nanomolar level. In this perspective, in the present study we report on a direct electrochemical determination of glyphosate in drinking water, at nanomolar levels, by some new gold nanoelectrode arrays onto graphene paper, without any analyte derivatization nor electrode functionalization. Field emission scanning electron microscopy, x-ray photoelectron spectroscopy, cyclic voltammetry and amperometry techniques were used for the nanoelectrode array characterization. Present nanoelectrodes showed high selectivity and their overall properties pave the way for a glyphosate sensor device competitive with respect to the existing sensors.