Fluorescence detection of glyphosate based on G-quadruplex and porphyrin metalation

In this paper, a fluorescence biosensor was developed for detection of glyphosate (GLYP) based on G-quadruplex (G4) and porphyrin metalation. In this strategy, G4 was utilized to increase the fluorescence of N-methyl-mesoporphyrin IX (NMM) and to catalyze the insertion of Cu2+ into NMM. Because Cu2+-NMM had no fluo-rescence, the fluorescence of NMM was quenched by Cu2+ in the absence of GLYP. However, in the presence of GLYP, it can bind to Cu2+ to inhibit the NMM metalation and the fluorescence was recovered. This GLYP biosensor did not require any modification and can complete the detection process in 23 min. To our knowledge, this was the first time using the porphyrin metalation to detect GLYP. The limits of detection (LOD) of this GLYP biosensor in water, rice, maize, and wheat samples were 0.065 mu\M, 0.13 mu M, 0.14 mu M, and 0.27 mu M, respectively. Meanwhile, this GLYP biosensor can selectively identify GLYP among organophosphorus pesticides. The satis-factory recovery rates in agricultural products (88.0-103%) suggested this biosensor had great application prospects for measuring GLYP.

Automated summary

In this paper, a fluorescence biosensor based on G-quadruplex (G4) and porphyrin metalation was developed for detection of glyphosate (GLYP). The biosensor utilized G4 to enhance the fluorescence of N-methyl-mesoporphyrin IX (NMM) and catalyze the insertion of Cu2+ into NMM. GLYP can bind to Cu2+ to inhibit NMM metalation and recover the fluorescence. The biosensor showed great application prospects for measuring GLYP with high recovery rates in agricultural products.