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A fast and effective analytical method with biomass solid‐phase microextraction sorbent combined with a high‐performance liquid chromatography‐ultraviolet detector was proposed for the determination of benzoylurea (BU) insecticides in tea products. The novel sorbent was prepared by activating and then carbonizing water hyacinth with a fast growth rate and low application value as raw material and showed a high specific surface area and multiple interactions with analytes, such as electrostatic action, hydrogen bonding, and π‐π conjugation. After optimizing the three most important extraction parameters (pH [X1], sample loading rate [X2], and solution volume [X3]) by Box‐Behnken design, the as‐established analytical method showed good extraction performance: excellent recovery (80.13%–106.66%) and wide linear range (1–400 µg/L) with a determination coefficient of 0.9992–0.9999, a low limit of detection of 0.02–0.1 µg/L and the satisfactory practical application results in tea products. All these indicate that the water hyacinth‐derived material has the potential as a solid‐phase extraction sorbent for the detection and removal of BU insecticides from tea products, and at the same time, it can also achieve the effect of rational use of biological resources, maintaining ecological balance, turning waste into treasure, and achieving industrial production. [ABSTRACT FROM AUTHOR]

By introducing functional groups such as quaternary amine groups, sulfonic acid groups, triazine groups, and other mespore nanomaterials into the hydrogel, better separation effect of some organic framework materials has been obtained. Due to a reasonable design and preparation strategy, the hydrogel composite-modified silica can be used in the selective separation of various analytes such as pesticides, alkylbenzenes, polycyclic aromatic hydrocarbons, nucleosides/bases, benzoic acids, antibiotics, and carbohydrates. Through the exploration of chromatographic retention behavior, it is proved that the column can be used in mixed-mode liquid chromatography. The intra-day relative standard deviation for retention time of this new stationary phase is 0.12–0.16% (n = 10), and the inter-day relative standard deviation is less than 0.39% (n = 5). This new stationary phase can also be used for separation in complex samples. The limit of detection (LOD) for chlorotoluron in farm irrigation water is 0.21 µg/L and the linear range is 2–250 µg/L. After optimizing the chromatographic conditions, the highest efficiency of the hydrogel column in RPLC and HILIC modes has reached 32,400 plates/m (chlorobenzuron) and 41,300 plates/m (galactose). This new type of hydrogel composite is a porous network material with flexible functional design and simple preparation method and its application has been expanded in liquid chromatography separation successfully. The hydrogel composed of triallyl cyanate cross-linking agent and 3-(2-(methacryloyloxy) ethyl) dimethylamine) propane-1-sulfonate (SBMA) monomer which were co-modified on the surface of mesoporous silica with MOF-919 for separation in mixed-mode liquid chromatography. [ABSTRACT FROM AUTHOR]

The ionogel material has functional designability and a network structure, so we designed this new ionogel@silica composite material that can be used as a stationary phase in liquid chromatography. 1-Allyl-3-vinylimidazolium tetrafluoroborate was bonded and chemically cross-linked on the surface of silica microspheres through the thiol olefin click reaction. Dodecanethiol was used as the end-capping group to prepare this new type of stationary phase. Infrared spectroscopy, elemental analysis, scanning electron microscopy, thermogravimetric analysis and other methods were used to demonstrate the successful preparation of this material. It can overcome the limited retention problem of purely hydrophilic group-modified chromatographic columns. Analytes such as nucleosides/bases, amino acids, sulfanilamides, polycyclic aromatic hydrocarbons and complex samples were separated and tested on ion gel-bonded chromatographic columns. The results show that the preparation of this new type of gel-bonded chromatographic column expands the possibility of applying gel materials in liquid chromatographic separation. This method provides a general method for easily incorporating various functional groups into chromatographic materials to develop stimulus-responsive liquid chromatography. [ABSTRACT FROM AUTHOR]

Inspired by porous smart gel materials, we designed pH-responsive polymer-modified silica microspheres as liquid chromatography stationary phase materials by a one-step strategy. The free radicals generated by the oxidation of dopamine are used to initiate the cross-linking polymerization of functional monomers. At the same time, the good adhesion of dopamine enables the polymer to be modified on silica. The hydrophilicity of this new stationary phase can change in response to the pH of the mobile phase and the stationary phase has weaker hydrophilicity under acidic (pH = 3.78) mobile phase conditions and stronger hydrophilicity under neutral mobile phase conditions. The hydrophilicity difference of the stationary phase leads to the selectivity difference in separation. To evaluate the chromatographic performance of this new stationary phase, 10 oligosaccharides and 9 nucleosides/bases were separated on this stationary phase. This paper will provide good guidance for us to achieve more pH-responsive hydrophilic/hydrophobic stationary phases in the future. [ABSTRACT FROM AUTHOR]