Zirconium(IV)‐based metal–organic frameworks (UiO‐67) as solid‐phase extraction adsorbents for extraction of phenoxyacetic acid herbicides from vegetables

Abstract

A zirconium(IV)-based metal organic framework, composed of 4,4'-biphenyldicarboxylic acid ligands and Zr O (OH) clusters, was successfully fabricated. Characterizations were performed on fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, Brunauer-Emmett-Teller, and thermogravimetric analysis, which confirmed that it possessed large specific surface area, high pore volume, and strong acid resistant stability. Furthermore, the prepared material containing biphenyl skeleton and a large number of Zr-O bonds, can grasp acid herbicides especially phenoxyacetic acid herbicides with aromatic structures through π-π interaction, hydrophobic interaction and Zr-O-H bonds. Based on these advantages, a method was developed for the determination of four phenoxyacetic acid herbicides from vegetable samples. Under the optimal conditions, wide linearities from 0.3 to 250 μg/L and low limits of detection from 0.1 to 0.5 μg/L were obtained. The intra- and interday relative standard deviations were 1.56-3.92 and 5.01-7.65%, respectively. The proposed method was applied to analyze phenoxyacetic acid herbicides residues in the tomato, cucumber, and white gourd samples. The satisfactory recoveries (86.12-103.44%) for the spiked samples in vegetable samples were achieved which demonstrated the method was an efficient pretreatment procedure and has a potential application for the trace determination of phenoxyacetic acids from a complex matrix.

Solid‐phase extraction of phenoxyacetic acid herbicides in complex samples with a zirconium(IV)‐based metal–organic framework

“…The TGA curve of MOF‐808 (see Supporting Information Figure S‐1B) showed that no mass loss appeared at 250°C. There was slow loss of mass between 450 and 600°C, which indicated that organic ligands were decomposed and ZrO 2 appeared after 600°C . Supporting Information Figure S‐1C was the FTIR spectra of MOF‐808.…”

“…The determination of various types of pollutants in various environmental substrates is particularly important for human development and environmental protection. As a type of major pollutants, pesticides are widely used in insecticide, weeding agriculture and public utilities, and phenoxyacetic acids (PAAs) are important herbicide in the agent . Common PAAs include dicamba, 4‐chlorophenoxyacetic acid, 2,4‐dichlorophenoxyacetic acid, and 2‐(2,4‐dichlorophenoxy)propionic acid and they can be widely distributed in the internal system of plants and thus enter the natural circulation system to cause certain harm, due to their extremely high water solubility, polarity, and good stability .…”

Ce-doped UiO-67 nanocrystals with improved adsorption property for removal of organic dyes

“…For the Ce-doped UiO-67, the characteristic peaks at 668 and 768 cm À1 are the longitudinal and transverse vibrations of the Zr-O bonds, 34,35 and the peaks at 1400-1600 cm À1 (labeled with purple stars) are corresponding to the stretching of O-C]O groups. 36 The peak at 1658 cm À1 is wider compared to that of the UiO-67, indicating that the Ce ions in the material are coordinating with the carbonyl group (C]O) of the BDC ligand. Additional a tiny bump in the peak at 1488 cm À1 is also seen due to the Ce-O stretching and Ce-O-C vibrations in the MOF, 37,38 demonstrating that Ce substitution to Zr takes place in the Ce-doped UiO-67.…”

Metal–organic framework for the extraction and detection of pesticides from food commodities

“…Extraction is the most important part of the sample preparation because the improper selection of the adsorbent will affect the final analysis results in the real sample, although other steps are flawless. Several excellent adsorbents have been prepared as adsorbent materials for different analytes in various sample matrices (Duo, Wang, Wang, Lu, & Liang, 2018). MOFs are a class of porous materials that have advantageous characteristics for pesticide extraction from food commodities.…”