A simple label free colorimetric method for glyphosate detection based on the inhibition of peroxidase-like activity of Cu(II)

The detection of glyphosate (Glyp) in water is of increasing importance because of its potential danger to environmental and health. In this study, a simple and label free colorimetric method for Glyp detection is proposed based on the inhibition of peroxidase-like activity of Cu2+. Cu2+ possesses the peroxidase-like activity that could catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) to oxidized TMB (oxTMB) in the presence of H2O2, resulting in a color change of the solution. However, the peroxidase-like activity of Cu2+ could be strongly hindered by Glyp due to the formation of Glyp-Cu2+ complexes. The color change of the solution or the absorbance change of oxTMB is utilized to monitor the concentration of Glyp. The linear range of the proposed method is 2-200 mu M and the detection limit is 1 mu M. Furthermore, as low as 10 mu M Glyp can be clearly distinguished by naked eyes. Also, this proposed method is successfully applied for screening Glyp in real samples and shows great promise for environmental monitoring owing to its simplicity, rapidness and high selectivity. (C) 2016 Elsevier B.V. All rights reserved.