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BACKGROUND: Weeds grow aggressively in agricultural fields, leading to reduced crop yields and an inability to meet the growing demand for food. Herbicides are currently the most effective method for weed control. However, the overuse of herbicides has resulted in the evolution of resistance mutants and has caused environmental pollution. Therefore, new technologies are urgently required to address this global challenge. RESULTS: We report a copper‐benzene‐1,4‐dicarboxylate metal organic framework (Cu‐BDC MOF)‐functionalized carboxyl hollow mesoporous silica (HMS‐COOH) delivery system for the pH‐controlled release of the acetyl‐CoA carboxylase (ACCase)‐inhibiting herbicide quizalofop‐p‐ethyl (QE). The delivery system (QE@HMS@Cu‐BDC) enabled the efficient control of barnyard grasses that are susceptible and resistant to ACCase‐inhibiting herbicides, which showed 93.33% and 88.33% FW control efficacy at 67.5 g ha−1, respectively. With the lowest pH value (3), QE and copper ion were released slowly to total 70.30% and 78.55% levels (respectively) from QE@HMS@Cu‐BDC after 89 h. QE@HMS@Cu‐BDC showed better absorption, conduction, transportation and ACCase activity inhibition performance than that of QE emulsifiable concentrate (EC) in both susceptible and ACCase‐herbicide resistant barnyard grasses. In addition, with the safener effect of carrier HMS@Cu‐BDC and the aid of the safener fenchlorazole‐ethyl (FE), the application of QE@HMS@Cu‐BDC was shown to mitigate the damage caused by QE to rice plants. CONCLUSION: This work found that the new material HMS‐COOH@Cu‐BDC can be used to mitigate herbicide‐induced oxidative stress and improve rice plant safety. Futhermore, the QE@HMS‐COOH@Cu‐BDC constructed in this research might be used as an efficient nanopesticide formulation for weed controls in paddy rice fields. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

A monolithic fiber of molecularly imprinted polymer (MIP) was prepared by in situ polymerization within the capillary with an inner diameter of 530 µm. It was carried out in 8 min by microwave irradiation using malachite green (MG) as a template molecule, α-methacrylic acid (MAA) as a functional monomer, acetonitrile (ACN) as a porogenic solvent, ethylene dimethacrylate (EDMA) as a crosslinker, azodiiso-butyronitrile (AIBN) as a thermal initiator. The resulted MIP fibers were pushed out from the capillary, eluted and inserted in the capillary again, which successfully used for the solid phase microextraction (SPME) procedure. The factors affecting the extraction of MG, such as the molar ratio of template/monomer (MG/MAA), concentration of NaCl, extraction and desorption time, and extraction and desorption solvents were investigated in detail. The selectivity of the MIP fibers was compared using MG analogues crystal violet (CV) and non-analogue Sudan II. It was also employed for the pretreatment of trace MG in the fish feed followed by high-performance liquid chromatography (HPLC) detection. Under the optimal conditions, the linear range of MG was 10-600 μg/L, the detection limit (LOD) was 1.23 μg/L and the recovery of spiked fish feed sample was 88.7∼113.9%. [ABSTRACT FROM AUTHOR]

In this paper, a novel monolithic stir bar based on molecularly imprinted polymer (MIP) was firstly developed by filling modified neodymium magnet (Nd2Fe14B) powders into a glass tube (60 × 4 mm), followed by the imprinted grafting with bisphenol A (BPA) as the template molecule by thermal polymerization. It has been successfully used for the stir bar sorptive extraction (SBSE) and its extraction performance illustrated that the MIP-encapsulated stir bar had stronger affinity to the template molecule, compared with the stir bar based on the non-imprinted molecularly polymer (NIP). Under the optimal extraction conditions, a simple method based on the coupling of MIP-SBSE with high performance liquid chromatography (HPLC) was used for the selective determination of the model mixtures of BPA, 4-phenylphenol (PP) and phenol (P) in bottled water. The recoveries of BPA, PP and P were in the range of 88.5-96.1%, 78.2-89.7%, 81.3-89.5% at three spiked levels, respectively, demonstrating that higher extraction and the specific absorption occurred between the template molecule and the prepared MIP stir bar. [ABSTRACT FROM AUTHOR]

In this paper, a simple, fast and in situ polymerization strategy to prepare monolithic molecularly imprinted polymer (MIP) fibers for solid phase microextraction (SPME) is developed using silica capillaries as molds. With the help of microwave irradiation, polymerization was carried out in 5.5 min using olivetol as a template molecular, α-methacrylic acid (MAA) as a functional monomer and ethylene dimethacrylate (EDMA) as a crosslinker, toluene and dodecanol as the binary porgens. The resulted MIP fibers were finally obtained after silica being etched away with a controlled length, and subsequently characterized by scanning electron microscope (SEM) and Fourier transform infrared absorption spectroscopy (FT-IR). Under the optimal extraction conditions, a simple method based on the coupling of MIP SPME with high performance liquid chromatography (HPLC) was used for the selective determination of the model mixtures of olivetol, phenol and m-toluidine in lake water and wheat bran samples. The recoveries of olivetol, phenol and m-toluidine for both samples were in the range of 87.3-93.6%, 21.4-27.2%, 18.9-24.8% at three spiked levels, respectively, demonstrating that higher extraction and the specific absorption occurred between the template molecule and the prepared MIP fiber. [ABSTRACT FROM AUTHOR]

In this paper, a new approach to prepare monolithic molecularly imprinted polymer ( MIP) fibers for solid-phase microextraction is proposed with the help of microwave irradiation. Imprinting polymerization was carried out within silica capillaries in 4.5 min, using dimethyl phthalate ( DMP) as a template molecular, α-methacrylic acid as a functional monomer and ethylene dimethacrylate as a crosslinker, acetonitrile as the porogenic solvent. The synthesis was optimized by varying the ratio of template/monomer and different volume of porogen. The resulted MIP fibers were obtained after silica being etched away with a controlled length of 1 cm, and subsequently characterized by SEM. In order to increase the selective extraction of DMP, factors affecting the extraction including extraction time, salt concentration, desorption time, and desorption solvents were investigated for solid-phase microextraction procedures in detail. The selectivity coefficients, defined as the extraction amount ratio of MIP to its nonimprinting fiber, were 5.6, 2.6, and 1.4 for DMP and its counterpart including dibutyl phthalate and di- n-octylo-phthalate, respectively. The resulted fibers were also applied to detect DMP, dibutyl phthalate, and di- n-octylo-phthalate in bottled beverage samples coupled to HPLC and resulted in relative recoveries of up to 73.8-98.5%, respectively. [ABSTRACT FROM AUTHOR]

Diamondback moth, Plutella xylostella (L.) is one of the most serious insect pests for its remarkable ability to develop resistance to virtually every insecticide that has been used against it. In the present study, amplified fragment length polymorphism (AFLP) is used to study the genetic differentiation as well as the effects of abamectin-selection on population genetic differentiation for P. xylostella. A dendrogram was constructed from the matrix of genetic distances using the STATISTICA software (Version 4.5) and unweighted pair-group method with arithmetic averages (UPGMA). The data demonstrated that compared to the susceptible strain (ABM-s), the heterozygosity in the abamectin-resistant strain (ABM-r) decreased with the increased selection pressure and resistant level. When the resistance ratio was below 4.3, there was no significant differentiation at the genome DNA level. When the resistance ratio reached 5.8, a fairly significant differentiation began to appear, and when the resistance ratio reached and exceeded 8.1, there appeared a significant genetic differentiation. The results suggest that abamectin selection is associated with increased genetic polymorphism in P. xylostella. [ABSTRACT FROM AUTHOR]