MIL-101(Cr) based d-SPE/UPLC-MS/MS for determination of neonicotinoid insecticides in beverages

Dihydroxyl modified UiO-66 as dispersive solid-phase extraction sorbent coupled with ultra-high performance liquid chromatography tandem mass spectrometry for detection of neonicotinoid insecticides

The extensive usage of neonicotinoid insecticides (NIs) has raised many concerns about their potential harm to environment and human health. Thus, it is of great importance to develop an efficient and reliable method to determine NIs in food samples. In this work, three Zr4+-based metal-organic frameworks functionalized with various numbers of hydroxyl groups were fabricated with a facile one-pot solvothermal method. Among them, dihydroxy modified UiO-66 (UiO-66-(OH)2) exhibited best adsorption performance towards five target NIs. Then, a sensitive and efficient method for detection of NIs from vegetable and fruit samples was established based on dispersive solid phase extraction (dSPE) with UiO-66-(OH)2 as adsorbent coupled with ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). Key parameters affecting the dSPE procedure including amounts of adsorbent, adsorption time, eluent solvents and desorption time were investigated. Under the optimal conditions, rapid adsorption of NIs within five minutes was achieved due to the high affinity of UiO-66-(OH)2 towards NIs. The developed method exhibited high sensitivity with limits of detection (LODs) varied from 0.003 to 0.03 ng/mL and wide linearity range over 3-4 orders of magnitude from 0.01 to 500 ng/mL. Furthermore, the established method was applied for determining trace NIs from complex matrices with recoveries ranging from 74.6 to 99.6 % and 77.0-106.8 % for pear and tomato samples, respectively. The results indicate the potential of UiO-66-(OH)2 for efficient enrichment of trace NIs from complex matrices.

A comparison of the determination of multiple pesticide residues in fruits, vegetables, and edible fungi using gas chromatography combined with filtration purification and solid-phase extraction

The multiplug filtration clean-up (m-PFC) and solid-phase extraction (SPE) pretreatment methods were employed to process 8 representative matrices in fruits, vegetables, and edible fungi, respectively. 37 pesticide residues were determined using gas chromatography equipped with ECD and FPD detectors. The measurement data were compared and analyzed following m-PFC purification and gas chromatography analysis, and both accuracy and precision met the (EU) 2021/808 requirements, achieving recovery rates for the 8 matrices ranging from 67.0% to 112.8% (averaging over 83.8% recovery), and RSDs between 0.2% and 15.2%. The 37 pesticides exhibited good linearity between 0.05 and 1.6 μg mL-1, and the matrix effect was found to be weaker compared to that of the Florisil solid-phase extraction method. The detection limits ranged from 0.0001 to 0.03 μg kg-1, with 31 pesticides showing lower detection limits compared to the SPE method. The application of this method to 150 real samples resulted in the detection of 17 pesticides across all samples. Fewer pigments were detected in m-PFC purified solutions compared to Florisil PR SPE when analyzed by liquid chromatography. m-PFC achieved more thorough adsorption of endogenous substances like pigments, reducing instrument contamination, utilizing less organic solvent, and simplifying the operation. This purification step offers clear advantages, allowing for the processing of larger sample batches in a short time. It can serve as a replacement for SPE methods like Florisi PR in batch detection of fruit and vegetable samples.

Fabrication of Nitrogen Based Magnetic Conjugated Microporous Polymer for Efficient Extraction of Neonicotinoids in Water Samples

Facile and sensitive methods for detecting neonicotinoids (NEOs) in aquatic environments are crucial because they are found in extremely low concentrations in complex matrices. Herein, nitrogen-based magnetic conjugated microporous polymers (Fe3O4@N-CMP) with quaternary ammonium groups were synthesized for efficient magnetic solid-phase extraction (MSPE) of NEOs from tap water, rainwater, and lake water. Fe3O4@N-CMP possessed a suitable specific surface area, extended π-conjugated system, and numerous cationic groups. These properties endow Fe3O4@N-CMP with superior extraction efficiency toward NEOs. The excellent adsorption capacity of Fe3O4@N-CMP toward NEOs was attributed to its π-π stacking, Lewis acid-base, and electrostatic interactions. The proposed MSPE-HPLC-DAD approach based on Fe3O4@N-CMP exhibited a wide linear range (0.1-200 µg/L), low detection limits (0.3-0.5 µg/L), satisfactory precision, and acceptable reproducibility under optimal conditions. In addition, the established method was effectively utilized for the analysis of NEOs in tap water, rainwater, and lake water. Excellent recoveries of NEOs at three spiked levels were in the range of 70.4 to 122.7%, with RSDs less than 10%. This study provides a reliable pretreatment method for monitoring NEOs in environmental water samples.

Design of hydroxyl-functionalized nanoporous organic polymer with tunable hydrophilic-hydrophobic surface for solid phase extraction of neonicotinoid insecticides

As being widely used insecticides, neonicotinoid residues are toxic and harmful to human health and aquatic ecosystems. Thus, the sensitive monitoring of neonicotinoids in water and food samples is highly desirable to reduce their risks to humans. Herein, four novel hydroxyl-functionalized nanoporous organic frameworks (OH-NOP1, OH-NOP2, OH-NOP3 and OH-NOP4) with tunable hydrophilic-hydrophobic surface have been designed and fabricated for the first time by employing luteolin as monomer and 4,4'-bis(chloromethyl)-1,1'-biphenyl as crosslinker at the molar ratio of 3:1, 1:1, 1:3 and 1:6, respectively. When the molar ratio of luteolin to crosslinker was 1:3, OH-NOP3 was obtained and it presented the highest affinity with excellent adsorption performance towards the studied neonicotinoids. The adsorption mechanism was proposed to be the strong hydrogen bond, polar interaction, Lewis acid-base interaction and pore adsorption between OH-NOP3 and neonicotinoids. Then, utilizing OH-NOP3 as sorbent for solid phase extraction cartridges, an effective method for extraction and preconcentration of neonicotinoids followed by high performance liquid chromatography analysis has been developed for quantitative detection of neonicotinoids from water and edible fungi. The method provided good linearity over the range of 0.06-100.0 ng mL^-1 for lake water, 1.5-100.0 ng g^-1 for pleurotus eryngii and sea-shroom. Low detection limit (at the signal to noise ratio of 3) was achieved in the range of 0.02-0.08 ng mL^-1 for water, 0.50-0.60 ng g^-1 for pleurotus eryngii and 0.50-0.80 ng g^-1 for sea-shroom, while the limit of quantification was 0.06-0.25 ng mL^-1, 1.50-1.80 ng g^-1 and 1.50-2.50 ng g^-1, respectively. Satisfactory method recoveries (85.1-112%) were obtained, with relative standard deviations below 8.2%. This study offered a new strategy for designing efficient sorbents to adsorb or remove organic pollutants based on the structure and properties of substrates.

A porous boron nitride nanorods-based QuEChERS analysis method for detection of five neonicotinoid pesticide residues in goji berries

To accurately determine neonicotinoid pesticide residues in goji berries, porous boron nitride nanorods (p-BNNRs) were prepared and used as a new QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) clean-up sorbent. Combined with ultrahigh-pressure liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), a modified QuEChERS method was developed to determine five neonicotinoid pesticide residues in goji berries. In goji berries, the p-BNNRs were shown to have a greater clean-up ability than typical clean-up materials (C18, PSA) The recoveries of the five targets ranged from 78.1 to 117.3% at three fortified levels, and the LODs ranged from 2.2 to 3.7 μg kg^-1. The results indicate that this approach could be successfully used to quickly determine of the five neonicotinoid insecticide residues in goji berries for risk assessment purposes, demonstrating the applicability and suitability of p-BNNRs for the routine evaluation of neonicotinoid insecticide residues in goji berries.