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

• We developed a photoelectrochemical biosensor for highly sensitive detection of glyphosate.
• The prepared photoelectrochemical biosensor was successfully utilized to detect practical samples.
• The proposed platform exhibited fine photoelectric conversion performance under light illumination.

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 nanosheets and photo-induced electrons could transfer to the electrode. Under the optimal conditions, the photocurrent change was proportional to the glyphosate concentration logarithmically with the wide liner range from 1.0 × 10−10 to 1.0 × 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.

Figure optionsDownload as PowerPoint slide