Online solid-phase extraction based on size-controllable spherical covalent organic framework for efficient determination of polybrominated diphenyl ethers in foods

Advances in covalent organic frameworks for sample preparation

Sample preparation is crucial in analytical chemistry, impacting result accuracy, sensitivity, and reliability. Solid-phase separation media, especially adsorbents, are vital for preparing of liquid and gas samples, commonly analyzed by most analytical instruments. With the advancements in materials science, covalent organic frameworks (COFs) constructed through strong covalent bonds, have been increasingly employed in sample preparation in recent years. COFs have outstanding selectivity and/or excellent adsorption capacity for a single target or can selectively adsorb multiple targets from complex matrix, due to their large specific surface area, adjustable pore size, easy modification, and stable chemical properties. In this review, we summarize the classification of COFs, such as pristine COFs, COF composite particles, and COFs-based substrates. We aim to provide a comprehensive understanding of the different classifications of COFs in sample preparation within the last three years. The challenges and development trends of COFs in sample preparation are also presented.

Development and validation of a green analytical method for simultaneously determining plasticizers residues in honeys from different botanical origins

A novel method has been proposed to determine nine plasticizers in honey samples by gas chromatography-mass spectrometry. An efficient sample treatment was proposed (average analyte recoveries between 77% and 118%) involving a double solvent extraction with ethyl acetate, followed by a clean-up step with florisil. Chromatographic analysis (< 21 min) was performed in an Agilent HP-5MS column under programmed temperature conditions. The greenness of the method was assessed with different tools that classified it as environmentally friendly. The method was validated in terms of selectivity, limits of detection (0.1-3.1 μg kg-1) and quantification (0.2-10.3 μg kg-1), linearity, matrix effect, trueness, and precision (relative standard deviation <9%). An analysis of thirty samples from different sources (commercial or experimental apiaries) revealed the presence of residues of five plasticizers in most of the samples. Finally, health risk assessment was evaluated, and the results indicated no associated health risks for consumers.

Extraction improvement of ionic liquid-functionalized silica by in situ anion-exchange for online solid-phase extraction of estrogens in honey

The accurate detection of analytes in honey is affected by the complex substrates, making it crucial to employ an effective sample preparation technique. In this work, an imidazolium ionic liquid was functionalized to the silica surface by a click reaction for solid-phase extraction (SPE) column, and in situ anion-exchange process was performed with different organic anions (dodecyl sulfonate, dodecyl benzene sulfonate, and naphthalene sulfonate). These SPE columns were evaluated through extracting the estrogens. The naphthalene sulfonate-based SPE column displayed the best extraction ability among these, and it was combined with high-performance liquid chromatography-diode array detection to establish an online enrichment and analysis system. Under the optimal test conditions, an online analytical method was developed, with high enrichment factors (1872-4744), wide linear ranges (0.0033-1.50, 0.0165-1.50, and 0.0330-1.50 μg g-1), and low detection limits (0.001-0.010 μg g-1). The method successfully determined several estrogens in some honey samples, and achieved satisfactory recovery results.