A diformyl-phenol-based fluorescent sensor for sensitive glyphosate detection via Zn(II) and Cu(II) coordination

Glyphosate (Glyp), one of the most widely used organophosphorus herbicides, extensively is applied for the control of invasive weeds. However, due to its potential toxicity to ecosystems and human health, the sensitive and selective detection of Glyp is of great importance. Herein, a novel diformyl phenol-based compound, 5-(tert-butyl)-2-hydroxy-1,3-phenylene)bis(methanylidene))bis(1H-pyrrole-2-carbohydrazide) (S1), was synthesized and its selectivity toward various metal ions was investigated. The results indicated that S1 exhibited high selectivity toward Cu^2 + and Zn²⁺ ions, leading to the formation of the corresponding metal complexes (S1 +Cu(II) and S1 +Zn). S1 +Cu(II) complex exhibited a pronounced fluorescence "turn-on" response upon interaction with Glyp, whereas S1 +Zn complex showed a slight fluorescence "turn-off" behavior under the same conditions. A concentration-dependent fluorescence response was obtained for Glyp in the 0-100 μM range, with limits of detection calculated as 3.0 nM for S1 +Cu(II) and 5.0 nM for S1 +Zn. Furthermore, quantitative analysis of Glyp with S1 +Cu(II) and S1 +Zn in real samples demonstrated the great potential of these complexes for practical applications.