A Novel SPME Fiber Chemically Linked with 1-Vinyl-3-hexadecylimidazolium hexafluorophosphate Ionic Liquid Coupled with GC for the Simultaneous Determination of Pyrethroids in Vegetables

Research progress of the combination of COFs materials with food safety detection

Covalent organic frameworks (COFs) have received lots of attention due to their multiple advantages such as high specific surface area, controlled pore size, and excellent stability. When detecting food contaminants, the matrix effect brought by complex food samples can significantly affect the accuracy of the results. How to attenuate matrix effect has always been a major challenge. Utilizing the advantages of COFs and applying them to detect food contaminants is currently a key research direction. The aim of this work is to provide a systematic summary of sample pretreatment techniques and detection techniques combined with COFs, which include almost all current techniques combined with COFs. In addition, the principles of combining COFs with different techniques are explained. Finally, the research foci and development direction of COFs in food contaminant detection are discussed. This is an important reference for the future development of food safety and the design of COFs.

Review: Microextraction Technique Based New Trends in Food Analysis

Food chemistry is the study and classification of the quality and origin of foods. The identification of definite biomarkers and the determination of residue contaminants such as toxins, pesticides, metals, human and veterinary drugs, which are a very common source of food-borne diseases. The food analysis is continuously demanding the improvement of more robust, sensitive, highly efficient, and economically beneficial analytical approaches to promise the traceability, safety, and quality of foods in the acquiescence with the consumers and legislation demands. The traditional methods have been used at the starting of the 20th century based on wet chemical methods. Now it existing the powerful analytical techniques used in food analysis and safety. This development has led to substantial enhancements in the analytical accuracy, precision, sensitivity, selectivity, thereby mounting the applied range of food applications. In the present decade, microextraction (micro-scale extraction) pays more attention due to its futures such as low consumption of solvent and sample, throughput analysis easy to operate, greener, robotics, and miniaturization, different adsorbents have been used in the microextraction process with unique nature recognized with wide range applications.

Thin Porous Poly(ionic liquid) Coatings for Enhanced Headspace Solid Phase Microextraction

In this contribution, thin poly(ionic liquid) (PIL) coatings with a well-defined pore structure built up from interpolyelectrolyte complexation between a PIL and poly(acrylic acid) (PAA) were successfully used for enhanced solid phase microextraction (SPME). The introduction of porosity with tunable polarity through the highly versatile PIL chemistry clearly boosts the potential of SPME in the detection of compounds at rather low concentrations. This work will inspire researchers to further explore the potential of porous poly(ionic liquid) materials in sensing and separation applications.

Sensitive Screening Method for Determination of Pyrethroids in Chicken Eggs and Various Meat Samples by Gas Chromatography and Electron Capture Detection

A sensitive and reproducible screening analytical method is described for the determination of six pyrethroids (phenothrin, permethrin, cyfluthrin, cypermethrin, deltamethrin, fenvalerate) in egg and meat samples by gas chromatography and electron capture detection (GC-ECD). A fast cleanup procedure, based on solid-phase extraction has been used, ensuring reduced solvent consumption and time and allowing the simultaneous preparation of multiple sample extracts. Under the optimal chromatographic conditions, an efficient separation was obtained with a total analysis time of less than 60 min, including the extraction-purification steps. Good responses for the six pyrethroids were obtained in a range of 50-500 μg L^-1, with linear coefficients higher than 0.9992. Instrumental limits of detection were between 0.22 and 0.63 μg L^-1, corresponding to 0.04 and 0.13 μg kg^-1 in the matrix. Detection limits in chicken eggs and various meat samples, calculated on spiked samples, were in the range 0.05-0.25 μg kg^-1 and 0.07-0.23 μg kg^-1, respectively. The validation results confirmed that the proposed GC-ECD method can be used as a reliable screening tool for the determination of pyrethroids in official check analyses. The method was extensively validated following the European directives, demonstrating its conformity in terms of selectivity, sensitivity, recovery, precision, and measurement uncertainty.

Three-dimensional hollow porous raspberry-like hierarchical Co/Ni@carbon microspheres for magnetic solid-phase extraction of pyrethroids

A three-dimensional magnetic hollow porous raspberry-like hierarchical Co/Ni@carbon microspheres (3D Co/Ni@carbon) were synthesized by using a bimetal-organic framework (Co/Ni-MOF) as a precursor and subsequent calcination under nitrogen. The 3D Co/Ni@carbon is a novel solid phase extractant that displays outstanding extraction capability and separation efficiency for the pyrethroid pesticides ethofenprox and bifenthrin. This is ascribed to the beneficial effects of facile analyte transport (due to the presence of free pores), the abundant number of adsorption sites (which warrant efficient extraction), and the excellent structural stability of the material. The 3D Co/Ni@carbon was applied to dispersive magnetic solid-phase extraction (d-MSPE), and the two pyrethroids were quantified by HPLC (UV detection wavelength: 220 nm). The method has a high preconcentration factor (937-1012) and give recoveries that range between 85.6-106.9%, with RSDs (for n = 5) of <6% in case of real samples. Graphical abstract The hierarchical porous Co/Ni@carbon microsphere as adsorbent was fabricated, and it showed high extraction efficiency for two pyrethroids.

Microextraction techniques for the determination of volatile and semivolatile organic compounds from plants: a review

Vegetables and fruits are necessary for human health, and traditional Chinese medicine that uses plant materials can cure diseases. Thus, understanding the composition of plant matrix has gained increased attention in recent years. Since plant matrix is very complex, the extraction, separation and quantitation of these chemicals are challenging. In this review we focus on the microextraction techniques used in the determination of volatile and semivolatile organic compounds (such as esters, alcohols, aldehydes, hydrocarbons, ketones, terpenes, sesquiterpene, phenols, acids, plant secondary metabolites and pesticides) from plants (e.g., fruits, vegetables, medicinal plants, tree leaves, etc.). These microextraction techniques include: solid phase microextraction (SPME), stir-bar sorptive extraction (SBSE), single drop microextraction (SDME), hollow fiber liquid phase microextraction (HF-LPME), dispersive liquid liquid microextraction (DLLME), and gas purge microsyringe extraction (GP-MSE). We have taken into consideration papers published from 2008 to the end of January 2013, and provided critical and interpretative review on these techniques, and formulated future trends in microextraction for the determination of volatile and semivolatile compounds from plants.