Binding-induced internal-displacement of signal-on photoelectrochemical response: A glyphosate detection platform based on graphitic carbon nitride

The exploitation and design of sensitive photoelectrochemical sensor with high performance materials is of great significance to expanding approaches for practical evaluation. Herein, a signal-on photoelectrochemical strategy with graphitic carbon nitride decorated Ag+ based on the binding-induced internal-displacement for glyphosate monitoring was established. The mechanism of this platform has been elaborately explored and the high sensitivity should be ascribed to two aspects. Firstly, graphite-like carbon nitride as visible light-active material possesses fine photocatalytic activity. The pyridine nitrogen units on g-C3N4 backbone could absorb Ag+ through chemical absorption and then photo-generated electrons would be reacted by Ag+, leading to the inhibition of electrons transfer and decrement of photocurrent. However, binding-induced internal-displacement of chelate effect between Ag+ and glyphosate, which promoted the constitution of current circuit and signal improvement owing to that Ag+ was deprived from the carbon nitride nano sheets and photo-induced electrons could transfer to the electrode. Under the optimal conditions, the photocurrent change was proportional to the glypho sate concentration logarithmically with the wide liner range from 1.0 x 10(-10) to 1.0 x 10(-3) M and a low detection limit of 30 pM. This economical and sensitive sensor system showed fine practicability which could be applied for broader applications. (C) 2015 Elsevier B.V. All rights reserved.