Conveniently and efficiently monitoring I- and Hg2+ in agricultural products or drinking beverages for the protection of human health is currently a great challenge. With this aim, a Ag-Pt bimetal quantum-dot nanozyme boosted by bioactive folic acid (FA@Ag-Pt QDs) was first developed for multichannel monitoring of I- and Hg2+ in this work using a two-step liquid-phase reduction method. Not only did the present FA@Ag-Pt QDs possess superior peroxidase-like activity with Michaelis constant (Km) and maximal reaction rate (Vmax) of 0.01 mM/2.95 × 10-8 M·s-1 and 1.15 mM/3.88 × 10-8 M·s-1, respectively, trace Hg2+ or I- could exclusively alter their enzyme-mimic performance with obvious color changes from blue to colorless or dark blue. I- could also strengthen the inherent fluorescence property of FA@Ag-Pt QDs. When applied for visual monitoring of I- and Hg2+ in real beverages or iodine-containing agricultural products, the detection recoveries were 93.9 %-105.3 % and 96.8-104.3 % with low detection limits of 6.56 × 10-8 mol/L and 4.00 × 10-10 mol/L (S/N = 3), respectively. The recovery and detection limit for fluorescent detection of I- were 95.8 %-104.1 % and 1.75 × 10-8 mol/L (S/N = 3), respectively. The mechanisms driving the improved peroxidase-like activity of FA@Ag-Pt QDs and their selective monitoring of Hg2+ and I- were illustrated in detail. The proposed FA@Ag-Pt QDs will act as an efficient sensor for the practical multichannel monitoring of Hg2+ and I-, with superior catalytic signal amplification.
Keywords: FA@Ag-Pt QDs; Hg(2+); I(−); Multichannel monitoring; Peroxidase-like.
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