High-sensitive determination of tetracycline antibiotics adsorbed on microplastics in mariculture water using pre-COF/monolith composite-based in-tube solid phase microextraction on-line coupled to HPLC-MS/MS.

Microplastics (MPs) act as carriers for organic pollutants (e.g. antibiotics) and microorganisms (e.g. bacteria) in waters, leading to the proliferation of antibiotic resistance genes. Moreover, the antibiotics adsorbed on MPs may exacerbate this process. For further research, it is necessary to understand the types and amounts of antibiotics adsorbed on MPs. However, due to the heavy work of MPs collection and sample pretreatment, there is a lack of analytical methods and relevant data. In this study, an in-tube solid phase microextraction (IT-SPME) on-line coupled to HPLC-MS/MS method based on amorphous precursor polymer of three-dimensional covalent organic frameworks/monolith-based composite adsorbent was developed, which could efficiently capture, enrich and analyze tetracycline (TCs) antibiotics. Under the optimal extraction parameters, the developed method was capable of detecting TCs at levels as low as 0.48-1.76 pg. This method was applied to analyze the TCs adsorbed on MPs of different particle sizes in mariculture water for the first time, requiring a minimum amount of MPs of only 1 mg. Furthermore, it was observed that there could be an antagonistic relationship between algal biofilm and TCs loaded on MPs. This approach could open up new possibilities for analyzing pollutants on MPs and support deeper research on MPs.

Task specific monolith for magnetic field-reinforced in-tube solid phase microextraction of mercury species in waters prior to online HPLC quantification.

In this study, a novel sorbent based on task specific monolith doped with Fe3O4 was in situ fabricated in capillary and acted as the extraction medium of magnetic field-reinforced in-tube solid phase microextraction (MFR/IT-SPME) to trap and preconcentrate mercury species which were coordinated with dithizone to form chelates. Various characterization technologies evidenced that the obtained monolithic adsorbent presented porous and super paramagnetic properties, and possessed abundant functional groups. Results evidenced that the implementation of magnetic field during extraction stages enhanced the extraction efficiency of studied Hg chelates from 48.5% to 75.3% to 69.9-94.4%. Under the optimized extraction parameters, the introduced MFR/IT-SPME was online coupled to HPLC/DAD to quantify mercury species at ultra-trace levels in various water samples. Limits of detection varied from 0.0067 µg/L to 0.016 µg/L, and the RSDs for precision were below 7.5%. Additionally, related extraction mechanism was deduced and revealed multiple forces co-contributed to the enrichment. The reliability and accuracy of suggested online approach for speciation analysis of mercury was well proved by confirmatory experiments.

Porous monolith-based magnetism-reinforced in-tube solid phase microextraction of sulfonylurea herbicides in water and soil samples.

In the present study, porous monolith-based magnetism-reinforced in-tube solid phase microextraction (MB-MR/IT-SPME) was first introduced to concentrate sulfonylurea herbicides (SUHs). To realize the effective capture of SUHs, a monolithic capillary microextraction column (MCMC) based on poly (vinylimidazole-co-ethylene dimethacrylate) polymer doped with Fe3O4 magnetic nanoparticles was in-situ synthesized in the first step. After that, the MCMC was twined with a magnetic coil which was employed to carry out variable magnetic field during adsorption and desorption procedure. Various important parameters that affecting the extraction performance were inspected in detailed. Results well indicated that exertion of magnetic field in the whole extraction procedure was in favor of the capture and release of the studied SUHs, with the extraction efficiencies increased from 36.8-58.1% to 82.6-94.5%. At the same time, the proposed MB-MR/IT-SPME was online combined to HPLC with diode array detection (HPLC/DAD) to quantify trace levels of SUHs in water and soil samples. The limits of detection (S/N = 3) for water and soil samples were in the ranges of 0.030-0.15 µg/L and 0.30-1.5 µg/kg, respectively. The relative standard deviations (RSDs) for intra- and inter-day variability were both less than 10%. Finally, the introduced approach was successfully applied to monitor the low contents of studied SUHs in environmental water and soil samples. Satisfying fortified recovery and precision were achieved.

Magnetism-reinforced in-tube solid phase microextraction for the online determination of trace heavy metal ions in complex samples.

For the first time, a convenient, online couplable, sensitive and environmentally friendly sample pretreatment method, namely, magnetism-reinforced in-tube solid phase microextraction (MR/IT-SPME) was proposed to effectively enrich heavy metal ions (HMIs). Monolithic capillary microextraction column embedded modified Fe3O4 magnetic nanoparticles (MCEN) was conveniently synthesized and employed as the microextraction column of MR/IT-SPME. Subsequently, the MCEN was put into a magnetic coil which was utilized to exert variable magnetic field during extraction procedure. Three HMIs, including Cu(II), Co(II) and Hg(II), were selected as studied ions and reacted with chelating agent sodium diethyldithiocarbamatetrihydrate to form metallic coordination compounds. The complexes were infused to the MCEN to perform the MR/IT-SPME extraction and then online determined by high-performance liquid chromatography equipped with diode array detection (HPLC-DAD). A series of key parameters affecting the extraction performance were investigated in detail. Results revealed that the exertion of magnetic field in adsorption and desorption steps favored the adsorption and release of the coordination compounds, with the extraction efficiencies enhanced from 47-65% to 67-89%. Finally, the developed online MR/IT-SPME-HPLC-DAD approach was successfully applied to determine studied HMIs in environmental water and seafood samples. The confirmatory experiments further evidenced the reliability and feasibility of the introduced approach for the analysis of trace HMIs in complex samples.

Metal-organic framework-monolith composite-based in-tube solid phase microextraction on-line coupled to high-performance liquid chromatography-fluorescence detection for the highly sensitive monitoring of fluoroquinolones in water and food samples.

In this study, a new metal-organic framework-monolith composite for in-tube solid phase microextraction phase (IT-SPME) of fluoroquinolones (FQs) was prepared. 4-Vinylbenzoic acid was copolymerized with ethylenedimethacrylate in a fused silica capillary to form porous monolith. After that, zeolitic imidazolate frameworks (ZIF-8) were synthesized in situ within the pores and the surface of the monolith by controlled layer-by-layer self-assembly of Zn2+ and imidazole. The introduction of ZIF-8 enhanced the surface area of monolith composite, and thus, improving the extraction performance of IT-SPME for FQs obviously. Under the optimized conditions, a highly sensitive method for the monitoring of FQs residue in water and honey samples was developed by the on-line combination of IT-SPME with high-performance liquid chromatography with fluorescence detection (HPLC-FLD). The limits of detection (S/N = 3) for the targeted FQs in water and honey samples were as low as 0.14-0.61 ng/L and 0.39-1.1 ng/L, respectively. The relative standard deviations (RSDs) for intra-day and inter-day assay variability were less than 10% in all samples. The established on-line IT-SPME-HPLC-FLD was successfully used to detect ultra-trace FQs in environmental water and honey samples. Recoveries at different spiked concentrations ranged from 80.1% to 119% and 80.2-117% for water and honey samples, respectively, with satisfactory reproducibility. Compared to up-to-date reported methods, the proposed approach exhibits some features such as high sensitivity, convenience, partial automation, low consumptions of sample and solvent.

On-line combining monolith-based in-tube solid phase microextraction and high-performance liquid chromatography- fluorescence detection for the sensitive monitoring of polycyclic aromatic hydrocarbons in complex samples.

An automated and sensitive method, consisting of monolith-based in-tube solid-phase microextraction (IT-SPME) coupled with high-performance liquid chromatography-fluorescence detection (HPLC-FLD), was developed for the monitoring of polycyclic aromatic hydrocarbons (PAHs) in water and milk samples. To enrich PAHs, a new poly (9-vinylanthracene-co-ethylene dimethacrylate) monolith was in-situ prepared and used as the adsorbent of IT-SPME. Various parameters affecting the extraction performance were investigated thoroughly. Under the optimal conditions, the synthesized monolith-based IT-SPME could enrich target PAHs effectively through π-π and hydrophobic interactions. Moreover, the developed on-line IT-SPME-HPLC-FLD method displayed satisfactory analytical merits for PAHs. The limits of detection (S/N = 3) for PAHs in water and milk samples were in the ranges of 0.017-0.23 ng/L and 0.10-2.36 ng/L, respectively. The relative standard deviations (RSDs) for intra-day and inter-day precisions with different spiked concentrations were below 9.8% and 11%, respectively. Finally, the proposed method was successfully applied to quantify ultra-trace target PAHs in water and milk samples. Several ng/L level PAHs were detected. Spiked recoveries achieved for water and milk samples were in the ranges of 78.5-118% and 75.5-119%, respectively. The RSDs varied from 0.30% to 10% for all analytes in all samples. In comparison with reported methods for the monitoring of PAHs, the present method exhibits some merits such as high sensitivity, automation of enrichment and determination procedure, low consumptions of sample and organic solvent.

Development of on-line monolith-based in-tube solid phase microextraction for the sensitive determination of triazoles in environmental waters.

In this work, a convenient and sensitive method for the determination of triazoles in environmental waters was developed by on-line combining in-tube solid phase microextraction (IT-SPME) and high performance liquid chromatography with diode array detector (HPLC-DAD). To extract triazoles effectively, poly (4-vinyl pyridine-co-ethylene dimethacrylate) monolith was in-situ fabricated and utilized as the extraction phase of IT-SPME. A series of key extraction parameters including desorption solvent, sample volume, adsorption and desorption flow rate, pH value and ionic strength in sample matrix were optimized thoroughly. Under the most favorable conditions (volume of sample, 6.0 mL; adsorption flow rate, 0.2 mL/min; desorption solvent, 80.0 µL mixture of ACN/water (70/30, v/v); desorption flow rate, 50.0 µL/min; sample pH value, 8.0; ionic strength did not be adjusted), the developed monolith-based IT-SPME could extract target analytes effectively and expected analytical merits were achieved. The limits of detection (S/N = 3) and limits of quantification (S/N = 10) were in the ranges of 0.014-0.031 µg/L and 0.11-0.074 µg/L, respectively. Satisfactory method reproducibility was obtained by intra-day and inter-day precisions, with relative standard deviations (RSDs) lower than 10%. The optimized IT-SPME-HPLC-DAD method was then applied to detect triadimenol, triazolone and hexaconazole in water samples including lake, river and sewage waters. The spiked recoveries were 78.9-106% and the RSDs were in the range of 0.2-7.2%. The results well evidence that the proposed method is convenient, accurate, sensitive, practical and environmentally friendly for the determination of triazoles in environmental waters.

Millifluidic chip with a modular design used as a sample pretreatment cartridge for flour and flour food products.

The integration of sample pretreatment remains one of the hurdles towards a rapid, automated micro total analytical system (µ-TAS) for real samples. In this paper, a modular design, which was used for sample preparation, has been developed as the polydimethylsiloxane (PDMS) millifluidic chips with channels at a millimeter level. Multiple functional units, including extraction, filtration, mixing and solid phase extraction (SPE), for sample pretreatment were integrated in one chip. In this chip, each functional unit was connected by pump tubings and one-way valves in series to form a fully automated system. Based on the modular design, multiple functional units have been combined in different sequences according to practical needs. In addition, the proposed system has characteristics of miniaturization, portability, and real-time application. Herein, spiked benzoyl peroxide (BPO) in flour samples was used as a model compound to study the system's performances. With a portable integrated Raman spectrometer for detection, the detection limit of BPO was 0.017gkg-1, with a linear relationship from 0.025 to 0.5gkg-1. This modular design was demonstrated to be effective and it can be expanded for pretreatment of other food samples.

miRNA-650 exerts anti-leukemia activity by inhibiting cell proliferation through Gfi1 targeting.

BACKGROUND:: Acute myeloid leukemia (AML) is the most common malignancy of the bone marrow with a high mortality. Recent advances in high-throughput sequencing have led to the identification of various miRNAs implicated in the pathogenesis of AML. We found in this study that miR-650, a miRNA that was traditionally considered to participate in the onset of hepatocellular carcinoma, might play a significant role in AML development and progression. METHODS:: qRT-PCR was used to detect the expression of miR-650 and Gfi1 in AML patients and healthy controls. Next, a luciferase assay was conducted to verify the target effect of miR-650 on Gfi1. Moreover, the CCK-8 assay was performed to evaluate the effect of miR-650 on the proliferation of AML cells in the presence and absence of Gfi1. RESULTS:: miR-650 was downregulated in AML whereas Gfi1 was upregulated. miR-650 could negatively regulate Gfi1 via direct targeting of its 3'-UTR, which was confirmed by luciferase assay. In addition, overexpression of miR-650 reduced cell proliferation in K562 cells, whereas an increase in cell proliferation was observed when K562 cells were transfected with miR-650 inhibitor, which was compromised in response to the knockdown of Gfi1. CONCLUSIONS:: Our research demonstrated that miR-650 modulates cell proliferation in AML through affecting the expression of Gfi1, which occurs by direct target action.