Electrochemical Nanobiosensor for Glyphosate Herbicide and Its Metabolite

The use of amperometric biosensor for the detection of glyphosate herbicide and its metabolite aminomethylphosphonic acid (AMPA) is presented. The biosensor was developed by electrochemically depositing poly(2,5-dimethoxyaniline) (PDMA) doped with poly(4-styrenesulfonic acid) (PSS) onto the surface of a gold electrode followed by electrostatic attachment of horseradish peroxidase (HRP) onto the PDMA-PSS nanocomposite film. The PDMA-PSS film was characterized by transmission electron microscopy (TEM) and Fourier Transform infrared (FTIR) spectroscopy. The HRP immobilized on the PDMA-PSS film catalyzed the reduction of hydrogen peroxide, the inhibition of which was applied in the detection of glyphosate and AMPA. The limits of detection of the biosensor for glyphosate and AMPA were 0.16 mu g L-1 and 1.0 mu g L-1, respectively. The study demonstrates that the biosensor is very sensitive and could be a useful tool in the screening of glyphosate and AMPA at low concentrations.