Ho2O3 activated Ag-based nanozymes for multi-signal monitoring and catalytic degradation of amoxicillin/cartap residues in alive agricultural food

Either antibiotic or pesticide residues are the most common pollutants found in agricultural food, seriously threatening human health and the ecological environment for survival. To efficiently monitor and remove them, rare-earth Ho 2 O 3 activated silver-based nanozymes (Ho 2 O 3 -Ag QDs) were identified in this work, taking advantage of high valence-engineering and intrinsic fluorescence property of Ho 2 O 3 . Target Ho 2 O 3 -Ag QDs exhibited superior peroxidase-like activity and fluorescence performance to their protosomatic Ag or Ho 2 O 3 nano particles. Trace amoxicillin or cartap could selectively alter its peroxidase-like activity or fluorescence property with clear hypochromic or “turn-on” fluorescence effect. Under optimal conditions, Ho 2 O 3 -Ag QDs were applied for multi-signal UV-vis/red-green-blue (RGB) monitoring of amoxicillin with detection limits (LOD) of 6.91 × 10 −8 M/1.18 × 10 −7 M, and “turn-on” fluorescence monitoring of amoxicillin/cartap with LODs of 3.56 × 10 −9 M/1.13 × 10 −9 M in aqueous, soil or agricultural products. Ho 2 O 3 -Ag QDs were also applied for on-site fluorescence imaging of amoxicillin, as an example, in consuming rice, alive zebrafish or leek flower samples with little influence. The multi-signal analytical reliability and the probable degradation mechanism were authenticated in detail.