Aptamer Trimode Biosensor for Trace Glyphosate Based on FeMOF Catalytic Oxidation of Tetramethylbenzidine.

The stable and highly catalytic Fe metal-organic framework (FeMOF) nanosol was prepared and characterized by electron microscopy, and energy and molecular spectral analysis. It was found that FeMOF strongly catalyzed the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by H2O2 to produce TMBox, which had a fluorescence (FL) peak at 410 nm. When silver nanoparticles were added, it exhibited strong resonance Rayleigh scattering (RRS) activity and surface-enhanced Raman scattering (SERS) effect. This new FeMOF nanocatalytic trimode indicator reaction was combined with the glyphosate aptamer reaction to establish a new SERS/RRS/FL trimode biosensor for glyphosate. The sensor can be used for the analysis of environmental wastewater, and a new method for detecting glyphosate content in wastewater is proposed. The linear range of the sensor is 0.1-14 nmol/L, the detection limit is 0.05 nmol/L, the recovery is 92.1-97.5%, and the relative standard deviation is 3.6-8.7%.