Easy and fast synthesis of MnCo-LDH yolk-shell spheres porous composites applied electrospinning nanofibers highly effective for extracting triazole fungicides

Today, the wide utilization of triazole fungicides due to environmental damage and its side effects has raised global concern. Thus, in this investigation, polyacrylonitrile/MnCo-layered double hydroxides nanofiber was synthesized and applied as an effective and novel adsorbent at thin-film solid-phase micro-extraction technique for the quick and concurrent extraction of five triazole fungicides in fruit and vegetable samples before quantitative analysis by high-performance liquid chromatography-ultraviolet. The incorporation of MnCo-layered double hydroxides with porous structure and abundant functional groups in a polymer medium improves the extraction efficiency of nanofibers owing to hydrogen bonding and π-π interactions formed between analytes and synthesized nano-adsorbent. Various important elements that affect the extraction efficiency of the intended analytes were optimized using a time-variable approach. Under the optimum conditions, the limit of detection and quantification range from 0.1 to 0.15 and 0.3-0.5 ng mL-1, respectively.

Vortex-assisted dispersive liquid-liquid microextraction based on the hydrophobic deep eutectic solvent-based ferrofluid for extraction and detection of myclobutanil

A vortex-assisted dispersive liquid-liquid microextraction (VA-DLLME) procedure using hydrophobic deep eutectic solvent-based ferrofluid (HDES-FF) as an extractant was established. The developed sample preparation method coupled with high-performance liquid chromatography-diode array detector (HPLC-DAD) was applied to the pretreatment and determination of myclobutanil (MYC) in fruit juice. Hydrophobic deep eutectic solvent, synthesized by n-decanoic acid and DL-menthol, was as a carrier and combined with magnetic nanoparticles (Fe3O4@OA) to form HDES-FF as an extractant with high extraction capacity. The synthesized materials were characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). Parameters affecting extraction efficiency were optimized using single-factor experiments and Box-Behnken design via response surface methodology (BBD-RSM). Parallel tests were performed three times under the optimal conditions predicted by the model, yielding an actual mean recovery of 94.77% with RSD of 2.7% (n = 3) and an enrichment factor of 41.8 ± 0.98 (mean value ± SD, n = 3). Under the optimal conditions, the linear range was 1.0-100.0 µg·mL-1; the limit of detection (LOD) and limit of quantification (LOQ) were 0.25 and 0.80 µg·mL-1, respectively. The average spiked recoveries in the samples ranged from 98.2 to 100.5% with intra-day relative standard deviations (RSDs) of 1.2-3.5% (n = 3) and inter-day RSDs of 1.1-3.8% (n = 3). Finally, the method was successfully applied to the determination of MYC antimicrobial agent in different fruit juice samples. The proposed HDES-FF-VA-DLLME/HPLC-DAD method was verified to widely apply to the extraction of triazole fungicides.

Combination of switchable hydrophilic solvent liquid-liquid microextraction with QuEChERS for trace determination of triazole fungicide pesticides by GC-MS

This work first proposed a novel green and efficient method based on Quick, Easy, Cheap, Efficient, Rugged, and Safe pretreatment (QuEChERS) combined with switchable hydrophilic solvent homogeneous liquid-liquid microextraction (SHS-HLLME) for trace determination of triazole fungicides (TFs) in agricultural products such as vegetables and fruits by gas chromatography-mass spectrometry (GC-MS). N,N-Dimethyl benzylamine was used for the synthesis of SHS. Box-Behnken design was applied for the optimization of extraction conditions and a mathematical model was obtained. Ultimately, 0.50 mL SHS, 1.0 mL 10 mol L^-1 sodium hydroxide, and 45 s ultrasonic time were determined as optimal conditions for the SHS-HLLME method. The limit of detection and limit of quantification determined using the optimal method (SHS-HLLME/GC-MS) were 0.13-0.27 ng mL^-1 and 0.43-0.90 ng mL^-1, respectively. In addition, the SHS-HLLME method under optimal conditions was combined with the traditional QuEChERS method to realize the advancement of the SHS-HLLME method from simple to complex matrix analysis, and the QuEChERS-SHS-HLLME method was successfully applied to the analysis of TFs in cucumbers, tomatoes, watermelon and grapes in agricultural products. Matrix-matched calibration standards were used to improve the accuracy of TFs in spiked cucumber samples to obtain recovery results close to 100%. It was shown that the new method is green and rapid, enabling fast and inexpensive sample pretreatment with up to 100-fold enrichment factor and low detection limit compared with the original QuEChERS method.

In-syringe temperature-controlled liquid-liquid microextraction based on solidified floating ionic liquid for the simultaneous determination of triazine and phenylurea pesticide in vegetable protein drinks

A novel in-syringe temperature-controlled liquid-liquid microextraction based on solidified floating ionic liquid (in-syringe TC-LLME-SFIL) combined with high performance liquid chromatography was developed for the simultaneous determination of monuron, chlorotoluron, atrazine, monolinuron, propazine and prometryn in commercial vegetable protein drinks. The samples were deproteinized by trichloroacetic acid and further cleaned up by solid phase extraction column. The ionic liquid tributyldodecylphosphonium tetrafluoroborate ([P_{4 4 4 12}]BF₄) was used as extraction solvent and dispersed into the depurated sample solution to form fine droplets with the assistance of heating and vortex. With the help of an ice bath, the ionic liquid phase solidified and floated on the surface of aqueous phase. After separation from the aqueous phase, the solidified ionic liquids were dissolved with acetonitrile and the resulting solution was analyzed by high performance liquid chromatography. Some extraction parameters, including type and amount of adsorbent, type and amount of ionic liquids, amount of NaCl, melting temperature and time of ionic liquid, vortex time, pH of sample solution, ice bath temperature and time, were investigated and optimized by single-factor experiment, Plackett-Burman design and Box-Behnken design. The results showed that good linearities (r ≥ 0.9994) were obtained in the concentration range of 7.8-1000.0 μg/L. The limits of detection and quantification were in the range of 0.25-2.59 μg/L and 0.82-8.63 μg/L, respectively. The spiked recoveries were 81.26-118.42% with the relative standard deviation (RSD, n = 3) lower than 8.17%. The present method was successfully applied to the simultaneous determination of triazine and phenylurea herbicides in vegetable protein drinks.

Assessment of magnetic core-shell mesoporous molecularly imprinted polymers for selective recognition of triazoles residual levels in cucumber

Functional magnetic nanomaterials based on molecular imprinting technique were successfully prepared on the surface of modified Fe₃O₄. Transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffractometer, and vibrating sample magnetometry were applied for characterization of the synthesized magnetic nanoparticles. The magnetic molecularly imprinted polymers (MMIPs) exhibited satisfactory magnetic response, specific recognition, and excellent adsorption capacity toward triazoles (maximum adsorption capacity of 9202.9 μg g^-1 for triadimefon). The obtained MMIPs were further used as magnetic dispersive solid-phase extraction (MDSPE) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) for detection of 20 triazoles in cucumber spiked at different levels. The mean recoveries were ranged from 79.9% to 110.3% and relative standard deviations (RSDs) were <11.2% (n = 5). Herein, we report a simple, rapid, environmentally friendly, and magnetic stuff recyclable approach for triazoles residual analysis in complicated agricultural products.

Development of a new emulsification microextraction method based on solidification of settled organic drop: application of a novel ultra-hydrophobic tailor-made deep eutectic solvent

In this research, a new microextraction method based on the solidification of settled organic drop (SSOD) was developed by coupling a novel tailor-made ultra-hydrophobic deep eutectic solvent (DES) with effervescence assisted emulsification microextraction.