De Zhang,Mingxin He,Chongyang Qin,Zhuoqun Wu,Minhui Cao,Dejiang Ni,Zhi Yu,Pei Liang
The unreasonable spraying and random migration of acetamiprid may cause pollution of crops, soil and water resources in the environment, resulting in threatening ecosystem and human health. However, the monitoring of acetamiprid using mass spectrum in the environment encounters challenges due to high-cost instruments and complex processing time. Herein, we fabricated a rapid and reliable SERS method based on Ag@ZIF-8@Au platforms for tracing acetamiprid residues in the environment. In this method, a MOF material named ZIF-8 is coated with silver nanoparticles and distributed internally between AgNPs and AuNPs to enhance Raman signal, which can enrich pesticide molecules into the hotspots area provided by noble material and helps avoid the oxidation of silver nanoparticles. High sensitivity (LOD of 9.027 × 10 -10 M for acetamiprid, and SERS enhancement factor of 4.3 × 10 7 ), excellent reproducibility (6.496% or 7.198% RSD for 30 random points) and superior stability (3.127% RSD for 6 weeks) were achieved using the proposed method. Acetamiprid with concentrations from 10 -4 to 10 -9 M were successfully detected by SERS method. Furthermore, the linear detection models of acetamiprid in different environment matrices (lake water, tea leaves, tea garden soil, oranges and oranges orchard soil) were established and all the correlation coefficient (R 2 ) were higher than or equal to 95%, indicating the excellent adaptability of Ag@ZIF-8@Au platform in environment. The randomly spiked concentrations of acetamiprid were also tested with good recovery values and low relative error values, further confirming the reliability of the detection method.
A core–shell–shell sandwich material is developed with silver nanowires as the core, ZIF-8 as an inner shell, and gold nanoparticles as the outer shell, namely, Ag@ZIF-8@Au nanowires (AZA-NW). Then, the synthesized AZA-NW is transformed into a surface-enhanced Raman spectroscopy (SERS) sensor (named M-AZA) by the vacuum filtration method and used to enrich, detect, and inactivate traces of bacteria in the environment. The M-AZA sensor has three main functions: (1) trace bacteria are effectively enriched, with an enrichment efficiency of 91.4%; (2) ultrasensitive detection of trace bacteria is realized, with a minimum detectable concentration of 1 × 101 CFU/mL; (3) bacteria are effectively killed up to 92.4%. The shell thickness of ZIF-8 (5–75 nm) is controlled by adjusting the synthesis conditions. At an optimum shell thickness of 15 nm, the effect of gold nanoparticles and ZIF-8 shell on the sensor’s stability, SERS activity, and antibacterial performance is investigated. The simulation of the SERS sensor using the finite difference time domain (FDTD) method is consistent with the experimental results, theoretically demonstrating the role of the gold nanoparticles and the ZIF-8 shell. The sensor also shows excellent stability, safety, and generalizability. The campus water sample is then tested on-site by the M-AZA SERS sensor, indicating its potential for practical applications.
Yue Wang,Quanying Qu,Xiao Xiao,Tianyu Wang,Han Yan,Wei Wu,Qinzhi Wang
In this work, a high-performance lychee-like plasmonic nanocomplex with programmable hierarchical structure (Ag@ZIF-8@Au) was successfully fabricated as surface enhanced Raman scattering (SERS) platform via layer-by-layer assembly for sensitive detection of diazepam (DZP). ZIF-8 has good pre-enrichment for DZP as well as works as a skeleton for preventing aggregation of plasmonic nanoparticles, dramatically boosting sensitivity, stability and reproducibility of the SERS substrate. Furthermore, lychee-like Ag@ZIF-8@Au nanostructures provided numerous SERS “hot spots” for generating the synergistic enhancement effects including lightning rod and resonance coupling effects. By leveraging Ag@ZIF-8@Au substrate, DZP can be exquisitely detected. The detection limit plummets to 0.126 ng mL −1 , while a broad linear detection span of 10 −9 –10 −2 g mL −1 is achieved. Additionally, Ag@ZIF-8@Au can be utilized to identify DZP in aquatic products with a satisfactory recovery rate of 85.3 % to 111.9 %, which indicates its good practical applicability and great potential for monitoring safety of aquatic products.
危险品化学品经营许可证（带存储）