Visual detection of glyphosate by Al3+-regulated carbon dots/CdTe quantum dots ratiometric fluorescent sensing platform.

Highly sensitive monitoring of pesticides has garnered attention for food safety. Here, a ratiometric fluorescent probe (AG-CDs-Al3+/CdTe QDs) was fabricated for specific and sensitive sensing of glyphosate. Surface modifications revealed the chelation-enhanced fluorescence process between the surface -OH of AG-CDs and Al3+. Positively charged green-emission AG-CDs-Al3+ assembled with negatively charged red-emission CdTe QDs, and photoinduced electron transfer (PET) occurred from CdTe QDs to AG CDs-Al3+. Glyphosate specifically coordinated with Al3+, causing remarkable variations in F500/F630 (linear range, 0.2-4.0 μM; detection limit, 5.7 nM) and a distinguishable green-yellow-red color change on the paper platform (linear range, 0.5-8.0 μM; detection limit, 26 nM). Furthermore, for real sample analysis, the sensor has the advantages of fast response (5 min), excellent accuracy (spiked recoveries, 95.0-105.0 %), high precision (relative standard deviation, < 3.33 %), and superior specificity, which endowed the designed sensing platform with great potential practicality in the field of food analysis.