[Advances in synthesis methods and applications of microporous organic networks for sample preparation].

Sample pretreatment is an essential step in chromatographic analysis. Solid phase extraction (SPE) is a widely used sample pretreatment method. In SPE, the quality of the adsorbent directly affects the adsorption and enrichment efficiency of the target compounds as well as the sensitivity and selectivity of the pretreatment and subsequent analysis.

System to screen and purify active ingredients from herbal medicines using hydrogel-modified human umbilical vein endothelial cell membrane chromatography coupled with semi-preparative high-performance liquid chromatography-offline-high-performance liquid chromatography-mass spectrometry.

Analytical screening and validation systems based on a combination of cell membrane chromatography and two-dimensional chromatography-tandem mass spectrometry are incapable of providing prepared samples containing the active ingredients found in traditional Chinese medicine; therefore, these samples cannot be directly used in subsequent studies. In this study, a semi-preparative cell membrane chromatography column was developed using a hydrogel-modified carrier and human umbilical vein endothelial cells to optimize prepared conditions, such as hydrogel polymerization, cell fragmentation, and cell membrane volume. This increased the binding ratio of membrane protein and carrier to 15.

An agaric-like covalent organic framework composite for efficient extraction of trace cytokinins in plant samples.

Covalent organic framework composites have received great interest and regarded as new-generation porous materials in application of sample preparation. In this work, an agaric-like graphene oxide @ covalent organic framework (AGO@COF) composite was first synthesized and used as an ideal adsorbent for enrichment of trace cytokinins (CKs) due to its large specific surface area, rich in micro-mesopore and organic functional groups. The contact areas between AGO@COF composite and CKs were greatly increased due to the special agaric-like morphology, which would further improve the extraction efficiency.

[Novel adsorption material for solid phase extraction in sample pretreatment of plant hormones].

Plant hormones (PHs) are of significance in plant growth, as they regulate the various processes related to plant growth, development, and resistance. Sensitive and precise quantitative analysis of PHs is a bottleneck in plant science research. Currently, liquid chromatography-tandem mass spectrometry is used for the accurate and efficient detection of PHs.

Antileukemic effects of indigo naturalis constituents by "target constituent knock-out" coupled with semipreparative liquid chromatography and quadrupole time-of-flight mass spectrometry.

A novel approach is presented to identify constituents with antileukemic properties in extracts of Indigo naturalis (Qingdai in Chinese). Target compounds (A , BC , and ABC ) that knocked out specific constituents displayed antileukemic effects in a total extract of I. naturalis and negative constituents (A , BC , and ABC ) that knocked out target compounds were separated, identified and knocked out by semipreparative liquid chromatography (semipreparative HPLC) and quadrupole time-of-flight mass spectrometer.

One-pot room-temperature synthesis of covalent organic framework-coated superhydrophobic sponges for highly efficient oil-water separation.

Frequent oil-spill accidents not only cause serious and long-term damage to marine ecosystems, but also lead to a huge loss of valuable natural resources. To lighten the environmental pollution of oil spills as quickly as possible, an efficient and environment-friendly approach for oil-water separation is highly desirable. Herein, a facile one-pot room-temperature approach was developed for large-scale fabrication of covalent organic framework-coated superhydrophobic sponges (sponges@COFs).

Self-assembly synthes is of trypsin-immobilized monolithic microreactor for fast and efficient proteolysis.

Fast and highly efficient digestion of proteins is essential for high-throughput proteomic analysis. Herein, a facile approach was developed for self-assembly preparation of trypsin-immobilized capillary monolithic column and its application as an immobilized enzyme microreactor (IMER) for fast and highly efficient proteolysis was described. The performance of the trypsin-immobilized monolithic enzyme microreactor was evaluated by in-situ digestion of model proteins.

Metal-organic framework-derived nitrogen-doped carbon nanotube cages as efficient adsorbents for solid-phase microextraction of polychlorinated biphenyls.

An efficient and stable adsorbent is of critical importance for solid-phase microextraction (SPME). In this study, we prepared metal-organic framework-derived nitrogen (N)-doped carbon (C) nanotube cages (N-CNTCs) with unique N-doped active sites and C-rich nanotubes to coat SPME adsorbents. This new material was obtained via a simple thermal treatment with ZIF-67, and exhibited high porosity and excellent chemical and thermal stability.

Electrospun UiO-66/polyacrylonitrile nanofibers as efficient sorbent for pipette tip solid phase extraction of phytohormones in vegetable samples.

In this work, metal-organic framework particles incorporated fibers (UiO-66/PAN nanofibers) were used as adsorbent in pipette tip solid phase extraction (PT-SPE) for the first time. The UiO-66/PAN nanofibers were fabricated by a facile electrospinning method and characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction and nitrogen adsorption-desorption experiments. The UiO-66/PAN nanofibers were applied to assemble a novel PT-SPE cartridge for determination of four phytohormones followed by high performance liquid chromatography (HPLC).

Prenatal levonorgestrel exposure induces autism-like behavior in offspring through ERβ suppression in the amygdala.

Background: Autism spectrum disorder (ASD) is characterized by impairments in social communication and restricted or repetitive behaviors or interests. ASD is now diagnosed in more than one out of 100 children and is biased towards males by a ratio of at least 4:1. Many possible explanations and potential causative factors have been reported, such as genetics, sex, and environmental factors, although the detailed mechanisms of ASD remain unclear.

Magnetic porous β-cyclodextrin polymer for magnetic solid-phase extraction of microcystins from environmental water samples.

Microcystins (MCs) are cyclic heptapeptide toxins and tumor promoters produced by cyanobacteria, which threaten the health of humans. In this study, magnetic porous β-cyclodextrin polymer (FeO@SiO@P-CDP) was synthesized and characterized by transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray spectrometry, Fourier transform infrared spectrometry, X-ray diffraction, nitrogen adsorption porosimetry and vibrating sample magnetometer. The synthesized FeO@SiO@P-CDP particles were then used for magnetic solid-phase extraction (MSPE) of MCs from environmental water samples, and exhibited excellent extraction performance, especially for MC-RR.

ERβ expression in the endothelium ameliorates ischemia/reperfusion-mediated oxidative burst and vascular injury.

Estrogen and estrogen receptors (ERs) have been reported to play protective roles in ischemia/reperfusion (I/R)-mediated injury, but the detailed mechanism remains to be fully understood. Nitric oxide (NO) and reactive oxygen species (ROS) also play important roles in the I/R process; however, due to the lack of sensitive and reproducible in vivo monitoring systems, we still do not have direct evidence for the effect of NO and ROS in vivo. In this study, we have established reliable in vivo monitoring systems to measure the variations in circulating ROS and NO during the I/R.

Ferrite nanospheres-based magnetic solid-phase extraction for determination of domoic acid in seawater samples using high-performance liquid chromatography with tandem mass spectrometry.

A simple, rapid and sensitive method for determination of trace levels of domoic acid (DA) in seawater was developed, based on a magnetic solid-phase extraction (MSPE) followed by high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS). Five kinds of ferrite magnetic nanospheres (MFe2O4; M=Fe, Co, Ni, Cu and Zn) were prepared and first used as sorbents for MSPE of DA and removal of salt interference. Under the same extraction and elution conditions, CuFe2O4 magnetic nanospheres provided the best pretreatment performance, which were then characterized in detail.

On-line concentration and pressurized capillary electrochromatography analysis of five β-agonists in human urine using a methacrylate monolithic column.

A pressurized capillary electrochromatography (pCEC) method combined with an online concentration was developed for the separation and determination of five β -blockers (terbutaline, salbutamol, formoterol, procaterol and salmeterol) in human urine. A stearyl methacrylate-based monolithic column was prepared as the separation column. The various separation parameters including acetontrile concentration, applied voltage, pH and concentration of the running buffer were investigated.

Simultaneous determination of plant hormones in peach based on dispersive liquid-liquid microextraction coupled with liquid chromatography-ion trap mass spectrometry.

Fruit development is influenced greatly by endogenous hormones including salicylic acid (SA) and abscisic acid (ABA). Mass spectrometry with high sensitivity has become a routine technology to analyze hormones. However, pretreatment of plant samples remains a difficult problem.

Novel multifunctional acceptor phase additive of water-miscible ionic liquid in hollow-fiber protected liquid phase microextraction.

In this paper, water-miscible ionic liquid (IL) such as 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) is introduced for the first time as a novel multifunctional acceptor phase additive in hollow-fiber protected liquid phase microextraction (HF-LPME). For investigating the performances of [BMIM]Cl, it was respectively mixed with NaOH, HCl and deionized water. And their extraction performance was preliminary evaluated with alkaline compounds (clenbuterol, metoprolol, carteolol and propranolol), acidic compounds (diethylstilbestrol, hexestrol, phenol and bisphenol A) and neutral compounds (acenaphthylene, fluorene and fluoranthene).

pCEC coupling with ESI-MS for the analysis of beta(2)-agonists and narcotics using a poly-(1-hexadecene-co-TMPTMA) monolithic column.

A pressure-assisted CEC with ESI-MS based on poly(1-hexadecene-co-trimethylolpropane trimethacrylate) monolithic column for rapid analysis of two beta(2)-agonists and three narcotics was established in this article. After the organic polymer-based monolithic column was prepared by an in-situ polymerization procedure, a systematic investigation of the pressure-assisted CEC separation and ESI-MS detection parameters was performed. Baseline separation of the studied analytes could be obtained using the solution containing 75% ACN v/v and 20 mmol/L ammonium acetate with pH 8.

A new method for the analysis of beta(2)-agonists in human urine by pressure-assisted capillary electrochromatography coupled with electrospray ionization-mass spectrometry using a silica-based monolithic column.

A new pressure-assisted capillary electrochromatography coupled with electrospray ionization-mass spectrometry method using a silica-based monolithic column as separation media was developed for the analysis of beta(2)-agonists in human urine. Experimental conditions including the mobile phase, separation voltage, assisted pressure, and sheath liquid were optimized for the analysis: mobile phase composed of 82% (v/v) ACN and 18% (v/v) 20mmol/L ammonium acetate (pH 6.0); separation voltage 25kV; assisted pressure 2 bar; and the sheath liquid consisting of 7.

Extraction and analysis of auxins in plants using dispersive liquid-liquid microextraction followed by high-performance liquid chromatography with fluorescence detection.

Auxin plays an important role in cell differentiation, apical dominance, and tropism in plants. A new method based on dispersive liquid-liquid microextraction (DLLME) combined with high-performance liquid chromatography-fluorescence detection (HPLC-FLD) has been established to detect auxin. A mixture of CHCl(3) (extraction solvent) and acetone (disperser solvent) was injected quickly into a sample solution with desired salt concentration and pH value, and then a cloudy solution consisting of many dispersed fine droplets of CHCl(3) was formed.

Simultaneous analysis of endogenetic and ectogenic plant hormones by pressurized capillary electrochromatography.

Pressurized CEC (pCEC) with UV detection was developed for the simultaneous analysis of endogenetic and ectogenic plant hormones. Effects of some crucial factors including mobile phase, buffer concentration, pH value and applied voltage on pCEC separation were investigated, respectively. Under the optimum conditions, namely a packed capillary column (3 microm Hypersil C(18), 45 cm total length with 100 microm id x 20 cm effective length) as the separation channel; ACN: 10 mmol/L phosphate (50:50, v/v, %) as the mobile phase, pH 4.

Preparation and evaluation of the highly cross-linked poly(1-hexadecane-co-trimethylolpropane trimethacrylate) monolithic column for capillary electrochromatography.

In this paper, a novel highly cross-linked porous monolithic stationary phase having a long alkyl chain ligand (C16) was introduced and evaluated in CEC. The monolithic stationary phase was prepared by in situ copolymerization of 1-hexadecene, trimethylolpropane trimethacrylate, and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) in the presence of ternary porogenic solvent (cyclohexanol/1,4-butanediol/water). In preparing monoliths, the ternary cross-linker trimethylolpropane trimethacrylate was usually applied to preparing molecularly imprinted polymers or molecularly imprinted solid-phase extraction, instead of binary cross-linker ethylene dimethacrylate.

Rapid analysis of peptides and amino acids by CE-ESI-MS using chemically modified fused-silica capillaries.

The objective of this study was to prepare a coated capillary to achieve rapid analysis of peptides and amino acids (AAs) by CE-ESI-MS. The coated capillary was prepared by chemical modification of the fused silica (FS) capillary with 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) via a silanization reaction followed by an on-column in situ graft polymerization. In preparing capillary coating, AMPS was introduced for the following two purposes: first, to achieve strong and stable EOF in a wide pH range, and second, to obtain good repeatability of separations of peptides and AAs by reducing their adsorption to the FS capillary.

Identification and quantitation of auxins in plants by liquid chromatography/electrospray ionization ion trap mass spectrometry.

Auxin is an important phylohormone, which regulates specific physiological responses such as division, elongation and differentiation of cells. A new method using liquid chromatography/electrospray ionization ion trap mass spectrometry (LC/ESI-ITMS) has been developed for identification and quantitation of four auxins. Under the optimum conditions, four auxins (indole-3-acetic acid, indole-3-propionic acid, indole-3-butyric acid and 1-naphthylacetic acid) were completely separated and quantitated within 7 min with a minimum detection limit of 8.