Glass slides functionalized by 1-carboxyethyl-3-methylimidazolium chloride for the determination of triazine herbicides in rice using high-performance liquid chromatography

Determination of remdesivir in human plasma using (deep eutectic solvent-ionic liquid) ferrofluid microextraction combined with liquid chromatography

A microextraction technique based on ferrofluids was developed for the preconcentration and quantification of Remdesivir in human plasma samples. This method utilized a new type of magnetic colloids created by combining silica-coated magnetic particles with modified ionic liquid and natural hydrophobic deep eutectic solvent as the carrier liquid. The efficiency of the sorption and desorption steps was optimized using a chemometrics approach. Under the optimized conditions, the calibration curve exhibited linearity in the concentration range of 0.5 to 500.0 μg L-1, with a limit of detection and quantification of 0.2 and 0.5 μg L-1, respectively. The method precision was evaluated by assessing intra- and interday precision at three different analyte concentrations, yielding values of 8.9% and 16.8%, respectively. Moreover, the method accuracy fell within the range of 90.9% to 107.5%. This proposed method offers a green and environmentally friendly sample preparation technique for conducting pharmacodynamic, pharmacokinetic, and therapeutic drug monitoring studies of Remdesivir in biological fluids. Importantly, this technique eliminates the need for external energy sources or the use of dispersive solvents, providing a more efficient and sustainable approach.

Electrospun composite nanofibers modified with silver nanoparticles for extraction of trace heavy metals from water and rice samples: An highly efficient and reproducible sorbent

Herein, a composite of polyacrylonitrile (PAN)/agar/silver nanoparticles (AgNPs) electrospun nanofibers was fabricated and applied as an efficient sorbent for thin-film micro-extraction (TFME) of five metal ions followed by inductively coupled plasma optical emission spectroscopy (ICP-OES). Incorporating agar into the nanofibers followed by in situ photo-reductive reaction under UV-lamp resulted in highly uniform dispersion of AgNPs in the nanofibers. Under the optimized conditions, agreeable linearity was acquired in the range of 0.5-250.0 ng mL^-1 (R² ≥ 0.9985). The LODs (based on S/N = 3) were attained in the range of 0.2 to 0.5 ng mL^-1. The relative standard deviations (RSDs) were between 4.5% and 5.6% (intra-day, n = 5) and 5.3%-5.9% (inter-day, n = 3) for three sequential days. The developed method was investigated with water and rice samples, and recoveries (93.9-98.0%) indicated that the PAN/agar/AgNPs could be a promising film for the adsorption of heavy metal ions in varied samples.

Cellular toxicity and pharmacokinetic study of butachlor by ultra-performance liquid chromatography-tandem mass spectrometry based on tandem mass spectrometry cubed technique

Butachlor is an aromatic amide compound that plays a role as a herbicide, a xenobiotic, and an environmental contaminant. The aim of this work was to develop a highly selective and sensitive ultra-performance liquid chromatography-tandem mass spectrometry method based on the tandem mass spectrometry cubed technique to determine butachlor in a biological matrix. Butachlor and internal standard acetochlor were separated on a Waters Acquity ultra-performance liquid chromatography BEH C₁₈ column (2.1 × 50 mm, 1.7 μm) with gradient elution using 0.1% formic acid aqueous solution (A) and acetonitrile (B) as mobile phases. The transitions selected for tandem mass spectrometry cubed quantitative analysis in positive ion mode were: for butachlor, mass-to-charge ratio 312.2→238.1→162.1; for acetochlor, mass-to-charge ratio 270.1→224.0→148.1. The total running time for each sample was 5.5 min. The ultra-performance liquid chromatography-tandem mass spectrometry cubed method showed a linear relationship (R² ≥ 0.995) in the concentration range of 0.5-100 ng/ml. The intra and interday accuracies are within the range of -10.6%-4.3% and precisions are between 4.48% and 13.14%. The novelty of the method is the use of tandem mass spectrometry cubed scanning mode, which improves selectivity and sensitivity. The results indicated that butachlor was cellular toxic. The safety of butachlor should be considered when it is used as a herbicide.

Preparation and evaluation of a chitosan modified biochar as an efficient adsorbent for pipette tip-solid phase extraction of triazine herbicides from rice

The low allowable limit of triazine herbicides (THs) in rice makes it imperative to develop novel sample pretreatment methods for extraction and preconcentration of THs. Herein, a phosphoric acid activated biochar (PBC) was prepared and modified by chitosan (CS). For THs with different polarities, CS-PBC with multiple interaction sites exhibited satisfactory chemisorption. On this basis, a CS-PBC-based pipette tip-solid phase extraction (PT-SPE) was developed combined with HPLC to extract THs from rice. Low limits of detection (1.41-3.35 ng g^-1), satisfactory linearity (0.01-2.00 μg g^-1, R² > 0.9974) and recoveries (96.13-116.25 %) were obtained with acceptable inter-day and intra-day precision (RSD ≤ 13.60 %). CS-PBC showed superior performance to three commercial single-mode adsorbents and comparable results to a hydrophilic-lipophilic balance adsorbent. The study explored the feasibility of PT-SPE for extracting THs from rice and broadened the application of plant biochar as an environmentally-friendly matrix in food sample pretreatment.

Improved photocatalyst: Elimination of triazine herbicides by novel phosphorus and boron co-doping graphite carbon nitride

A non-metallic and low-cost novel phosphorus and boron co-doping graphite carbon nitride (PB-g-C₃N₄) photocatalyst was prepared by a facile thermal copolymerization of urea with B₂O₃ and (NH₄)₂·HPO₄. The novel PB-g-C₃N₄ exhibited excellent optical and electrical properties and the photocatalytic elimination efficiency for atrazine (AT, can make feminization of male frogs in the wild, and even induce reproductive cancers in humans.) has been greatly improved compared with the pristine g-C₃N₄. The results of characterization techniques indicate that the introduced B and P atoms most probably to substitute for sp²-hybridized C atoms in triazine rings. O₂^- and h⁺ are the dominant active species to induce the elimination of AT demonstrated by the radical-trapping experiments. And a possible elimination pathway is proposed according to the detected main intermediates. In addition, PB-g-C₃N₄ was applied to the simultaneous photocatalytic elimination of 9 triazine herbicides, and the effects of different initial concentrations, pH, fulvic acid (FA) and ion species on their elimination effects were studied. And it was proved that the photocatalytic performance of PB-g-C₃N₄ did not significant decrease after 4 times of reuse.

Microwave absorption medium-assisted extraction coupled with reversed-phase dispersive liquid-liquid microextraction of triazine herbicides in corn and soybean samples

A new extraction method, microwave absorption medium-assisted extraction coupled with reversed-phase dispersive liquid-liquid microextraction, was developed for the determination of triazine herbicides in corn and soybean samples. Triazine herbicides were extracted with hexane and then directly enriched into the ionic liquid phase. The purification of sample and concentration of target analytes were performed simultaneously. The method combines the advantages of nonpolar solvent dynamic microwave extraction and reversed-phase dispersive liquid-liquid microextraction, which could greatly simplify the operation and reduce the whole pretreatment time. The Box-Behnken design was used to the optimization of experimental factors involved in the dynamic microwave-assisted extraction. In the present study, good linearity in the range of 5.00-500.00 µg/kg was obtained. The limits of detection and quantification varying from 1.3 to 4.2 and 4.1 to 13.9 µg/kg were achieved, respectively. The intra- and interday precisions were between 2.7 and 6.9%. The present method was applied to the analysis of corn and soybean samples, and the recoveries of analytes ranged from 80.7 to 106.9% with the relative standard deviations of 2.1-7.8%. The present method shows the potentials of practical applications in the treatment of the complex fatty solid samples.

One-step synthesized magnetic MIL-101(Cr) for effective extraction of triazine herbicides from rice prior to determination by liquid chromatography-tandem mass spectrometry

The magnetic metal-organic framework MIL-101(Cr) material-based solid-phase extraction method coupled with high-performance liquid chromatography and tandem mass spectrometry was applied to extract seven triazine herbicides in rices. Fe₃ O₄ /MIL-101(Cr) was synthesized using reduction-precipitation method, in which steps including pre-synthesis and modification of Fe₃ O₄ nanoparticles were by-passed. Various parameters including extraction solvent type and volume, ultrasonic extraction time, amount of Fe₃ O₄ /MIL-101(Cr) microspheres, adsorption time, desorption volume and time were investigated. Under optimal conditions, the proposed method had the limit of detection (S/N = 3) and the limit of quantification (S/N = 10) of 1.08-18.10 and 3.60-60.20 pg/g, respectively. Relative standard deviations calculated for all herbicides with concentrations of 2 and 20 ng/g were in the range of 0.5 to 13% (n = 3). In addition, at the two above-mentioned concentrations, the method achieved relative recoveries percentages of 79.3 to 116.7% when applied to determine the triazine herbicides in real samples spiked. This rapid, green, non-polluting, pre-concentrated extraction method was successfully developed and applied to analyze herbicides in rice samples.