Rapid determination of pesticide residues in fruit and vegetable using Au@AgNPs decorated 2D Ni-MOF nanosheets as efficient surface-enhanced Raman scattering substrate

Abstract

Herein, a core-shell Au@Ag nanoparticles modified 2D Ni-MOF nanosheets (Ni-MOF-Au@AgNPs) surface-enhanced Raman scattering (SERS) substrate was prepared for fast determination of pesticide residues in fruit and vegetable samples. Au@AgNPs with controllable sizes were in-situ grown onto 2D Ni-MOF nanosheets to modulate the electromagnetic enhancement. Moreover, 2D MOF nanosheets endowed the Ni-MOF-Au@AgNPs substrate with fast adsorption and separation capacity to positively charged targets within 10–15 min. The Ni-MOF-Au@AgNPs SERS substrate with dense Au@AgNPs distribution exhibited high enhancement factors of 2.2 × 106, 3.7 × 105, and 9.5 × 105 to thiram, diquat, and paraquat, respectively. Subsequently, the Ni-MOF-Au@AgNPs substrate was used for the quantification of thiram, diquat, and paraquat in range from 0.01 to 50 mg/L with detection limits of 87.1, 188.8, and 8.9 μg/L, respectively. The recoveries of thiram, diquat, and paraquat during food sample analysis were 80.6–105%, 87.8–102%, and 80.0–113%, with relative standard deviations of 1.0–6.2%, 1.4–7.7%, and 1.6–7.4% (n = 3), respectively. The whole analysis process could be finished within 30–45 min. Such a robust 2D Ni-MOF-Au@AgNPs substrate with well-defined structure and good SERS activity has great potential for fast food safety monitoring and environmental analysis.