Molecularly Imprinted Dual-Responsive Extraction for Avenanthramides Using Covalent Organic Frameworks Doped with Polyethyleneimine-Modified Mn-ZnS Quantum Dots

A Review on the Applications of Quantum Dots in Sample Preparation

In recent years, despite significant advances in preconcentration and preparation techniques that have led to efficient recovery and accurate measurement of target compounds. There is still a need to develop adsorbents with unique and efficient features such as high pore volume and surface area, reactivity, easy synthesis, low toxicity, and compatibility with the environment, which increase the adsorption capacity and increase extraction efficiency. Semiconductor nanocrystals called quantum dots (QDs) with a size of less than 10 nm are three-dimensional nanoparticles with a spherical, rod, or disc structure that have significant potential in extraction as adsorbents due to their excellent properties such as low toxicity, reactivity, environmental friendliness, and hydrophilic and hydrophobic interactions. One of the most basic issues in the development of adsorbents is to increase the effective surface and, as a result, their extraction efficiency. QDs, having an effective surface much higher than conventional nanomaterials, are a suitable option for extracting target compounds in different environments. This work comprehensively reviews QD-based extraction methods and surface modification strategies of QDs based on functional groups, ligands, and materials from 2013 to 2024. In addition, the applications of QD-based composites for the extraction of organic and inorganic analytes (residues of drugs in human blood and plasma, toxins, pesticides, pollutants from chemical industries, heavy metals, etc.) in different matrices are investigated.

Determination of benzimidazoles in fruits by open-tubular capillary electrochromatography based on ionic liquids grafted covalent organic frameworks

A novel capillary electrochromatography method has been developed for the simultaneous quantification of ten benzimidazole fungicides in fruits. Herein, covalent organic frameworks (COFs) and ionic liquids (ILs) were successfully introduced to prepare open-tubular capillary column to improve the loading capacity and separation performance. The parameters effecting the analytical performance including pH and concentration of running buffer, separation voltage and the addition of organic solvent were investigated systematically. Under the optimized conditions, the method allowed the baseline separation of ten benzimidazole fungicides, and showed a good linearity in the range of 3.5-200 μg kg^-1 with the detection limits between 1.0 and 2.8 μg kg^-1. The intraday and interday precisions for recoveries were lower than 7.9% and 12.2%, respectively. Intraday and interday precisions for their retention times were lower than 3.2% and 6.6%, respectively. Satisfactory recoveries for grape, pear and orange samples at two concentrations were obtained ranging from 85.0 to 95.9% with RSDs lower than 7.8%, demonstrating the potential applications of the open-tubular capillary electrochromatography method for trace benzimidazole fungicides analysis in fruits.

Functional Hybrid Micro/Nanoentities Promote Agro-Food Safety Inspection

The rapid development of nanomaterials has provided a good theoretical basis and technical support to solve the problems of food safety inspection. The combination of functionalized composite nanomaterials and well-known detection methods is gradually applied to detect hazardous substances, such as chemical residues and toxins, in agricultural food products. This review concentrates on the latest agro-food safety inspection techniques and methodologies constructed with the assistance of new hybrid micro/nanoentities, such as molecular imprinting polymers integrated with quantum dots (MIPs@QDs), molecular imprinting polymers integrated with upconversion luminescent nanoparticles (MIPs@UCNPs), upconversion luminescent nanoparticles combined with metal-organic frameworks (UCNPs@MOFs), magnetic metal-organic frameworks (MOFs@Fe₃O₄), magnetic covalent-organic frameworks (Fe₃O₄@COFs), covalent-organic frameworks doped with quantum dots (COFs@QDs), nanobody-involved immunoassay for fast inspection, etc. The presented summary and discussion favor a relevant outlook for further integrating various disciplines, like material science, nanotechnology, and analytical methodology, for addressing new challenges that emerge in agro-food research fields.