Aryl ketones-derived porous organic polymer for enrichment and sensitive detection of phenylurea herbicides in water, tea drink and mushroom samples.

Three aryl ketones-derived porous organic polymers (ATP-POPM, ATP-POPP and ATP-POPO) were fabricated through the aldol condensation reaction of acetylated triphenylsilane precursor (ATP) with different aromatic aldehydes for the first time. The ATP-POPM exhibited superior extraction capacity toward phenylurea herbicides (PUHs). A sensitive method for the simultaneous determination of six PUHs in water, tea drink and mushroom samples was developed with ATP-POPM as solid phase extraction adsorbent prior to high performance liquid chromatography ultraviolet detection. Under the optimized conditions, the linear response of PUHs was 0.09-80.0 ng mL-1 for water, 0.18-100.0 ng mL-1 for tea drinks and 4.50-200.0 ng g -1 for mushroom samples. The detection limits (S/N=3) of the method were 0.03-0.10 ng mL-1, 0.06-0.18 ng mL-1, 1.50-4.50 ng g -1 for water, tea drink and mushroom, respectively. The method recoveries for spiked samples were in the range of 80.7%-116.0%, with relative standard deviations less than 10.3%. The results proved that the established method was sensitive and suitable to detect PUHs with acceptable accuracy and precision. This work provided a powerful tool to synthesize promising adsorbent by aldol condensation reaction for detecting six PUHs simultaneously in real samples.

Simvastatin Inhibits Endometrial Cancer Malignant Behaviors by Suppressing RAS/Mitogen-Activated Protein Kinase (MAPK) Pathway-Mediated Reactive Oxygen Species (ROS) and Ferroptosis.

This paper was designed to explore the function of simvastatin as a chemotherapeutic drug on the endometrial cancer (EC) cell proliferation, invasion, and ferroptosis. Firstly, a number of in vitro experiments were conducted to determine the impact of different treatments of simvastatin on the Ishikawa cell invasion, proliferation, and colony formation. The concentration of DCFH-DA-labeled reactive oxygen species (ROS) in cells was assessed by flow cytometry. Enzyme-linked immunosorbent assay (ELISA) was performed to examine the intracellular contents of Fe2+, malondialdehyde (MDA), and glutathione (GSH). Additionally, Western blot was utilized to measure the expression level of RAS/mitogen-activated protein kinase (MAPK)-related proteins and ferroptosis-related proteins in cells. The results showed that simvastatin at 10 µM and 15 µM apparently suppressed the proliferation of Ishikawa cells, colony formation, and invasion ability of Ishikawa cells, and upregulated the level of MDA and ROS, but downregulated the level of GSH. Besides, 10 µM and 15 µM of simvastatin promoted cell ferroptosis (up-regulation of Fe2+ and TRF 1 protein level; down-regulation of SLC7A11 and FPN protein level) and lowered the RAS, p-MEK, and ERK protein level. Furthermore, experiments also revealed that the inhibitory effects of simvastatin on Ishikawa cell proliferation, colony formation, and invasion, as well as the promoting effects on oxidation and ferroptosis were reversed. All in all, simvastatin reduces the RAS/MAPK signaling pathway to inhibit Ishikawa cell proliferation, colony formation, and invasion, and promote cell oxidation and ferroptosis. This paper demonstrates the potential of simvastatin as a new anticancer drug for EC.

Effective solid-phase extraction of chlorophenols with covalent organic framework material as adsorbent.

In this work, a porous extended network covalent organic framework designated as TP-NDA-COF was synthesized by the reaction of 2,4,6-trihydroxy-benzene-1,3,5-tricarbaldehyde (TP) and 1,5-naphthalenediamine (NDA). The structure and morphology of the TP-NDA-COF was characterized by means of Fourier transform infrared spectra (FT-IR), thermal gravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscope (SEM). The TP-NDA-COF was applied as a solid-phase extraction adsorbent for the extraction of some chlorophenols from water and lemon black tea beverage samples prior to high performance liquid chromatography-UV detection. The main experimental parameters that affect the extraction efficiency including the type and volume of eluent, sample solution volume, sample loading rate and sample solution pH were investigated. Under the optimal conditions, the calibration curves were linear in the range of 0.30-60.0 ng mL-1 with the determination coefficients (R2) of 0.9996-0.9998 for water samples and in the range of 0.60-60.0 ng mL-1 with the R2 values from 0.9990 to 0.9996 for beverage samples. At the signal to noise ratio of 3 (S/N = 3), the method LODs for the analytes were 0.10-0.15 ng mL-1 for water samples and 0.20-0.50 ng mL-1 for lemon black tea beverage, respectively. Good repeatability was achieved with the relative standard deviations of less than 7%. The results showed that the SPE-HPLC method can be used for the determination of chlorophenols in environmental water and foodstuffs samples.

Facile synthesis of conjugated microporous polymer with spherical structure for solid phase extraction of phenyl urea herbicides.

A carbazolic conjugated microporous polymer (designated as CZ-CMP) was successfully synthesized through Scholl reaction of carbazole with 1, 3, 5-triphenylbenzene. The CZ-CMP was characterized by FT-IR spectrum, X-ray diffraction, nitrogen sorption isotherms, and scanning electron microscopy. The characterization results showed that the CZ-CMP had a spherical structure with high surface area and good microporosity. Its adsorption performance was investigated by applying it as an adsorbent for the solid phase extraction (SPE) of phenyl urea herbicides (PUHs) (metoxuron, chlortoluron, isoproturon, monolinuron and buturon) from tea drinks samples prior to high performance liquid chromatographic detection. The CZ-CMP displayed high extraction efficiency for the PUHs, and the primary factors affecting the SPE efficiency including the type and volume of the eluent, sample solution pH, sample loading rate and sample volume were optimized. Under the optimized conditions, a good linear response for the analytes was observed in the range of 0.10-80.0 ng mL-1 with correlation coefficients (r) from 0.9937 to 0.9997. The limits of detection were measured to be in the range of 0.02-0.30 ng mL-1 and the limits of quantitation were in the range of 0.06-0.9 ng mL-1. The developed method was successfully applied for the determination of the five PUHs in four different kinds of drinks with the method recoveries between 83.7% and 118% and the relative standard deviations between 1.0% and 10%. Besides, the application potential of the CZ-CMP was evaluated by using it to extract different types of the organic compounds including some phthalate eaters (PAEs), chlorophenol (CPs), nitroimidazoles and polycyclic aromatic hydrocarbons (PAHs). The results indicated that the CZ-CMP had strong adsorption ability for the compounds with more hydrogen bonding sites and moderate hydrophobicity.

Ferrocene-based nanoporous organic polymer as solid-phase extraction sorbent for the extraction of chlorophenols from tap water, tea drink and peach juice samples.

Ferrocene-based nanoporous organic polymer (Fc-NOP) was used as solid-phase extraction (SPE) adsorbent and showed excellent adsorption capacity for chlorophenols (CPs) compared with commercial C18 and multi-walled carbon nanotubes. Then, a SPE method with Fc-NOP packed cartridge combined with HPLC-UV detection was developed to determine CPs in tap water, black tea drinks and peach juice samples. Under optimal conditions, the detection limits of the method measured at the signal to noise ratio of 3 (S/N = 3) were 0.04-0.06 ng mL-1 for tap water and 0.10-0.20 ng mL-1 for black tea drinks and peach juice samples. Satisfactory method recoveries were achieved in the range of 87.6-119% with relative standard deviations of 3.11-7.83%. Result proved that this method was a sensitive and efficient method for determination of trace CPs in foods. The extraction result for more other compounds confirmed that the developed method had a great application potential for analysis of other trace pollutants in food samples.

Phosphorous-enriched knitting aryl network polymer for the rapid and effective adsorption of aromatic compounds.

A phosphorous-enriched knitting aryl network polymer (named as Ph-PPh3-KAP) was fabricated by one-step crosslinking between triphenylphosphine and benzene, with formaldehyde dimethyl acetal as an external crosslinker. The Ph-PPh3-KAP had a large surface area and good physicochemical stability. Its adsorption performance for aromatic organic compounds was evaluated by using some dyes and benzene ring-containing compounds as the model adsorbates. The results exhibited that it had a rapid and effective adsorption for the aromatic organic compounds due to the hydrogen bonding and polar interactions of the Ph-PPh3-KAP with the target compounds. Then, the Ph-PPh3-KAP was explored as the adsorbent for the solid phase extraction of some phenylurea pesticides from lake water, tomato and cucumber samples prior to HPLC analysis. Under optimal conditions, the linear responses of the phenylurea pesticides were 0.1-100 ng mL-1 for lake water and 0.5-100 ng g-1 for cucumber and tomato samples. The limits of detection for the analytes at S/N = 3 were 0.01-0.02 ng mL-1 for lake water and 0.03-0.05 ng g-1 for cucumber and tomato samples. The recoveries were in the range from 80.8% to 118%. The Ph-PPh3-KAP exhibited a great application potential for extraction of aromatic compounds.

Magnetic porous carbon derived from a Zn/Co bimetallic metal-organic framework as an adsorbent for the extraction of chlorophenols from water and honey tea samples.

A novel magnetic porous carbon derived from a bimetallic metal-organic framework, Zn/Co-MPC, was prepared by introducing cobalt into ZIF-8. Magnetic porous carbon that possesses magnetic properties and a large specific surface area was firstly fabricated by the direct carbonization of Zn/Co-ZIF-8. The prepared magnetic porous carbon material was characterized by scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, N2 adsorption, and vibrating sample magnetometry. The prepared magnetic porous carbon was used as a magnetic solid-phase extraction adsorbent for the enrichment of chlorophenols from water and honey tea samples before high-performance liquid chromatography analysis. Several experimental parameters that could influence the extraction efficiency were investigated and optimized. Under the optimum conditions, good linearities (r > 0.9957) for all calibration curves were obtained with low limits of detection, which are in the range of 0.1-0.2 ng mL(-1) for all the analytes. The results showed that the prepared magnetic porous carbon had an excellent adsorption capability toward the target analytes.

[Study on the interaction of genistein and human serum albumin by spectroscopic method].

The interaction of genistein and human serum albumin (HSA) was investigated by fluorescence quenching spectra, synchronous fluorescence spectra and ultra-violet absorption spectra. The results showed that the quenching mechanism of the intrinsic fluorescence of HSA by genistein is due to the formation of genistein-HSA complex, resulting in a static quenching procedure. The binding constants (KA) were 1.00 x 10(6) (27 degrees C), 1.66 x 10(6) (37 degrees C) and 5.25 x 10(6) (47 degrees C), respectively. According to the Förster theory of non-radiation energy transfer, the binding distances (r) were 2.59 nm (27 degrees C), 2.65 nm (37 degrees C) and 2.90 nm (47 degrees C), respectively. The thermodynamic parameters showed that the binding power between genistein and HSA is mainly the electrostatic interaction Synchronous spectrum was used to investigate the conformational change of HSA.

[Interaction between strychnine and bovine serum albumin].

AIM: To study the interaction between strychnine and bovine serum albumin. METHODS: Fluorescence spectroscopy and ultraviolet spectroscopy were used. RESULTS: The static quenching and the non-radiation energy transfer are the two main reasons to leading the fluorescence quenching of BSA. The apparent combining constants (K(A)) between strychnine and BSA are 3.72 x 10(3) at 27 degrees C, 4.27 x 10(3) at 37 degrees C, 4.47 x 10(3) at 47 degrees C and the combining sites are 1.01 +/- 0.03. The combining distance (r = 3.795 nm) and energy transfer efficiency (E = 0.0338) are obtained by Förster's non-radiation energy transfer mechanism. CONCLUSION: The interaction between strychnine and BSA was driven mainly by hydrophobic force.

Analysis of Strychnos alkaloids in traditional Chinese medicines with improved sensitivity by sweeping micellar electrokinetic chromatography.

The application of an on-line sweeping preconcentration method in micellar electrokinetic chromatography (MEKC) for the determination of Strychnos alkaloids, namely strychnine and brucine, has been investigated in this work. After experimental optimizations, the best separation was achieved in 50 mmol l(-1) H3PO4 (pH 2.0) containing 100 mmol l(-1) SDS and acetonitrile in a ratio of 4:1 (v/v), with an applied voltage of -20 kV at 20 degrees C. The sample matrix consisted of 100 mmol l(-1) H3PO4 (pH 2.0), and sample introduction was performed at 0.5 psi for 270 s, with photodiode array detection at 203 nm. Compared with the conventional MEKC injection method, up to 100-fold improvement in concentration sensitivity was achieved in terms of peak height by using this sweeping injection technique. In the method, the compound berberine was used as the internal standard for the improvement of the experimental reproducibility. The calibration curve was linear over a range of 0.5-15 microg ml(-1) for both strychnine and brucine, with a correlation coefficient of 0.998 and 0.997, respectively. The detection limits (S/N=3:1) for strychnine and brucine were 0.05 and 0.07 microg ml(-1), respectively. The sweeping-MEKC method has been successfully applied to the analysis of strychnine and brucine in Strychnos nux-vomica L. and its Chinese medicinal preparations.