Yuan Tian

Surface-imprinted polymers (ZIF-67@MIPs) supported by ZIF-67 were prepared by precipitation polymerization using enrofloxacin (ENR) as the template molecule, methacrylic acid as the functional monomer, and ethylene glycol dimethacrylate as the cross-linker. ZIF-67@MIPs were characterized by Fourier transform infrared spectrometry, X-ray diffraction, scanning electron microscopy, and particle size distribution. The adsorption performance of the polymer was studied. The adsorption equilibrium was reached within 30 min. The maximum adsorption was 9.02 μg·mg^-1. The imprinting factor was 2.58. The polymer was then used as a sorbent of a solid-phase extraction column for the separation and purification of ENR in real water samples. The extraction conditions were optimized. The method was established by high-performance liquid chromatography, and the linearity was verified by UPLC-MSMS. The correlation coefficient and limits of detection and quantification were 0.9999, 0.23 ng·mL^-1, and 0.76 ng·mL^-1, respectively. The recoveries were in the range of 83.79-100.68%; the relative standard deviation was 4.46-7.35%. The above data indicated that the method could be used for the separation and enrichment of ENR in real samples.

Developing a vacuum thermal desorption mass spectrometry method to facilitate analysis of volatile organic samples.

Ionic liquids found a wide application in catalysis and extraction due to their unique properties. Herein, ethylene glycol dimethacrylate as the cross-linker and 1-vinyl-3- butylimidazolium tetrafluoroborate as functional monomer via thermally initiated free-radical polymerization was prepared as a novel copolymer solid phase micro-extraction (SPME) coating. A surface modified stainless-steel wire was implemented as the substrate. Factors affecting the extraction performances of the copolymer, including the molar ratio of monomers to cross-linkers, the amount of porogen agent, and polymerization time were evaluated and optimized. To evaluate the extraction performance, five commonly seen polycyclic aromatic hydrocarbons (PAHs) were taken as the analytical targets. The potential factors affecting extraction efficiency were optimized. The as-prepared SPME device, coupled with gas chromatography, was successfully applied for the determination of PAHs in water samples. The wide linear range, low detection limit, good reproducibility, selectivity, and excellent thermal stability indicate the promising application of the newly developed SPME fiber in environmental monitoring as well as in other samples having complex matrices.

In this study, a new covalent organic framework, consisting of tetra(4‐aminophenyl)porphyrin and tris(4‐formyl phenyl)amine, was layer‐by‐layer immobilized on stainless‐steel wire as a coating for microextraction. The fabrication process was easy and controllable under mild conditions. The as‐grown fiber was applied to extract polycyclic aromatic hydrocarbons in aqueous solution via head‐space solid‐phase microextraction. Furthermore, it was analyzed by gas chromatography with a flame ionization detector. A wide linear range (0.1–50 µg/L), low limits of detection (0.006–0.024 µg/L, signal‐to‐noise ratio = 3), good repeatability (intra‐fiber, n = 6, 3.1–8.50%), and reproducibility (fiber to fiber; n = 3, 5.79–9.98%), expressed as relative standard deviations, demonstrate the applicability of the newly developed coating. This new material was successfully utilized in real sample extraction with a satisfactory result. Potential parameters affecting the extraction efficiency, including extraction temperature and extraction time, salt concentration, agitation speed, sample volume, desorption temperature, and time, were also optimized and discussed.