Exploring mother-daughter communication and social media influence on HPV vaccine refusal for daughters aged 9-17 years in a cross-sectional survey of 11,728 mothers in China.

This study investigated the influences of mother-daughter communication and social media on mothers' HPV vaccine refusal for their daughters aged 9-17. A cross-sectional online survey among 11,728 mothers of girls aged 9-17 in Shenzhen, China was implemented between July and October 2023. Multi-level logistic regression models were fitted. Among 11,728 participants, 43.2% refused to have their daughters receive an HPV vaccination. In multivariate analysis, more openness in the mother-daughter communication (AOR: 0.99, 95%CI: 0.98, 0.99), perceived more positive outcomes of mother-daughter communication (AOR: 0.77, 95%CI: 0.75, 0.79), higher frequency of exposure to testimonials about daughters' HPV vaccination (AOR: 0.81, 95%CI: 0.78, 0.85) and information encouraging parents to vaccinate their daughters against HPV on social media (AOR: 0.76, 95%CI: 0.73, 0.79), and thoughtful consideration of the veracity of the information specific to HPV vaccines (AOR: 0.80, 95%CI: 0.77, 0.83) were associated with lower vaccine refusal. Mothers who were not the main decision-makers of daughters' HPV vaccination (AOR: 1.28 to 1.46), negative outcome expectancies of mother-daughter communication (AOR: 1.06, 95%CI: 1.04, 1.08), and mothers' HPV vaccine refusal (AOR: 2.81, 95%CI: 2.58, 3.06) were associated with higher vaccine refusal for their daughters. The level of mothers' HPV vaccine refusal for their daughters was high in China. Openness and outcome expectancies of mother-daughter communication and information exposure on social media were considered key determinants of HPV vaccine refusal for daughters. Future HPV vaccination programs should consider these interpersonal factors.

Coverage with the First Dose of Human Papillomavirus Vaccination among Females Aged 9-50 Years in Shenzhen, China: A Surveillance Based on Administrative Health Records in 2023.

China started to offer human papillomavirus (HPV) vaccines to females aged 9-45 years in 2016. However, there was a lack of reports about HPV vaccination coverage in a representative sample of females in China. Therefore, this study aimed to examine the current HPV coverage and associated factors among females aged 9-50 years in Shenzhen, China, based on administrative health records kept by community health centers. A multistage random sampling approach was used. The research team randomly selected 18 community health centers in Shenzhen, and 3118 health records of females aged 9-50 years were then randomly selected from these health centers. Among all participants, 18.7% received at least one dose of HPV vaccination. The highest coverage was observed among females aged 18-26 years (23.4%), followed by those aged 27-35 years (22.0%) and 36-45 years (20.2%). Such coverage was very low among females aged 9-17 years (4.6%) and those aged 46-50 years (3.2%). Among females aged 18 years or above, higher education level, having a family doctor, and permanent residency in Shenzhen were associated with higher HPV vaccination coverage, while older age and being married/divorced were negatively associated with coverage. The HPV vaccination coverage in Shenzhen was 18.7% and there is a strong need for improvement.

Urchin-like fluorinated covalent organic frameworks decorated fabric for effective self-cleaning and versatile oil/water separation.

Oil contamination and industrial organic pollutants emission have been a serious problem affecting the ecological and residential environment. Membrane-based separation shows great application prospect due to its low-cost, environmental-friendly and easy operation. Therefore, the development of efficient oil-water separation membranes is highly desirable. Herein, a fabric filter with superwettability was prepared by coating urchin-like fluorinated covalent organic frameworks (COFs) on fabric, which was well utilized in filtering immiscible oil-water mixture and surfactant-stabilized water-in-oil emulsion driven only by gravity for the first time. The as-prepared COF fabric filter (defined as fabric@u-FCOF) possessed many outstanding properties, including superhydrophobicity with the water contact angle of approximately 151.6°, satisfactory resistance for alkaline, acidic and saline environments, as well as superior mechanical durability under harsh conditions. Because of the super-micropore of fabric@u-FCOF and the nanopore in the COF coating, the obtained fabric@u-FCOF exhibited excellent performances in terms of separation efficiency and permeability, in which the oil flux was up to 16964 L·m-1·h-2 and separation efficiency for the mixed o-dichlorobenzene/water was higher than 99.4%. In addition, the fabric@u-FCOF also showed excellent self-cleaning performance due to the micro/nano hierarchical structure of its surface. These excellent properties make it an ideal candidate for applications of oil/water separation and water purification.

Spatial Metabolomics and Lipidomics Reveal the Mechanisms of the Enhanced Growth of Breast Cancer Cell Spheroids Exposed to Triclosan.

Triclosan (TCS), an antimicrobial compound, is known to have potential endocrine-disruptive properties, but the underlying toxic mechanisms at the metabolic level are not well understood. Here, we applied metabolomics and lipidomics combined with mass spectrometry imaging (MSI) to unveil the mechanisms of the enhanced growth of MCF-7 breast cancer cell spheroids (CCS) exposed to TCS. To obtain a wide coverage of metabolites and lipids by using MSI, we used techniques of matrix-assisted laser desorption/ionization (MALDI) and MALDI coupled with laser-postionization. The results showed that TCS and TCS sulfate penetrated into the entire area at 0-3 h and both localized in the inner area at 6 h. After 24 h, a portion of two compounds was released from CCS. Omic data indicated that TCS exposure induced alterations via several pathways, including energy metabolism and biosynthesis of glycerophospholipids and glycerolipids. Further MSI data revealed that the enhancement of energy supply in the peripheral area and the increase of energy storage in the inner area might contribute to the enhanced growth of MCF-7 breast CCS exposed to TCS. This study highlights the importance of integrating metabolite distributions and metabolic profiles to reveal the novel mechanisms of TCS-triggered endocrine disrupting effects.

Spatial lipidomics and metabolomics of multicellular tumor spheroids using MALDI-2 and trapped ion mobility imaging.

Lipids and metabolites are small biological molecules that act major roles in cellular functions. Multicellular tumor spheroids (MCTS) are a highly beneficial three-dimensional cellular model for cancer research due to their ability to imitate numerous characteristics of tumor tissues. Increasing studies have performed spatial lipidomics and metabolomics in MCTS using matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI). However, these approaches often lack the sensitivity and specificity to offer a comprehensive characterization of lipids and metabolites within MCTS. In this study, we addressed this challenge by utilizing MALDI combined with laser-induced postionization (MALDI-2) and trapped ion mobility spectrometry (TIMS) imaging in H295R adrenocortical MCTS. Our results showed that MALDI-2 could detect more lipids and metabolites in MCTS than the traditional MALDI. TIMS data revealed a successful separation of many isomeric and isobaric ions of lipids and metabolites with different locations (e.g., proliferative region and necrotic region) within MCTS, suggesting an enhanced peak capacity for spatial lipidomics and metabolomics. To further identify these isomeric and isobaric ions, we performed MS/MS imaging experiments to compare the differences in signal intensities and spatial distributions of product ions. Our data highlight the strong potential of MALDI-2 and TIMS imaging for analyzing lipids and metabolites in MCTS, which may serve as valuable tools for numerous fields of biological and medical research.

In-situ growth of covalent organic framework on stainless steel needles as solid-phase microextraction probe coupled with electrospray ionization mass spectrometry for rapid and sensitive determination of tricyclic antidepressants in biosamples.

Tricyclic antidepressants (TCAs) including amitriptyline (AT), doxepin (DOX) and nortriptyline (NT) are the first-line drugs for the clinical treatment of depression; however, monitoring TCA concentrations in biological fluids and tissues is necessary to improve therapeutic effect and determine the cause of death in patients. It is of great significance to develop a rapid and sensitive method for real-time monitoring of TCAs in various biosamples. In this work, we fabricated a novel covalent organic framework (COF) based solid-phase microextraction (SPME) probe by an in-situ step-by-step strategy, which was obtained by sequentially modifying 1,3,5-tri (4-aminophenyl) benzene (TPB) and 2, 5-divinylbenzaldehyde (DVA) on the surface of polydopamine layer. The TPB-DVA-COF-SPME probe possessed high specific surface area (1244 m2·g - 1), regular pores (3.23 nm), good hydrophobicity and stability, resulting in efficient enrichment for TCAs. Furthermore, the combination of TPB-DVA-COF-SPME probe and ambient electrospray ionization mass spectrometry system (ESI/MS) was firstly proposed for rapid and sensitive determination of TCAs in biosamples. As a result, the developed method exhibited low limits of detection (LODs) (0.1-0.5 µg∙L - 1), high enrichment factors (39-218), and low relative standard deviations (RSDs) for one probe (1.2-3.8%) and probe-to-probe (2.0-3.7%). Benefiting from these outstanding performance, TPB-DVA-COF-SPME probe was further successfully applied to biosamples (i.e., serum, liver, kidney, and brain) with excellent reusability, indicating the promising applicability of the TPB-DVA-COF-SPME-ESI/MS as a powerful tool for drug monitoring.

Hydrophilic glutathione-modified flower-like hollow covalent organic frameworks for highly efficient capture of N-linked glycopeptides.

Highly efficient enrichment of N-glycopeptides from complicated biosamples based on mass spectrometry is essential for biomedical applications, especially in disease biomarker research. In this work, glutathione (GSH)-modified hierarchical flower-like hollow covalent organic frameworks loaded with Au nanoparticles (HFH-COFs@Au@GSH) were synthesized for N-glycopeptide enrichment. Due to the abundant accessibility sites, high specific surface area, and inherent high stability of the hierarchical flower-like hollow structure, a large number of Au NPs and hydrophilic GSH can be modified on the HFH-COFs. The HFH-COFs@Au@GSH displayed excellent hydrophilicity and remarkable enrichment performance for N-glycopeptides: low detection limit (0.1 fmol µL-1), large adsorption capacity (200 µg mg-1), great selectivity (1 : 1000, HRP to BSA), and good reusability (at least 5 times). Furthermore, the HFH-COFs@Au@GSH were successfully applied to capture N-linked glycopeptides in human serum, and 308 N-glycosylation peptides corresponding to 84 N-glycosylation proteins with 123 N-glycosylation sites were detected. Gene ontology analyses were used to elucidate the cellular component, biological process and molecular function of detected glycoproteins in human serum, demonstrating the great potential of the HFH-COFs@Au@GSH in N-glycopeptide enrichment for glycoproteomic analysis of complex biological samples.

Quantitative proteomic analysis of oxaliplatin induced peripheral neurotoxicity.

Oxaliplatin (OXA)-induced peripheral neurotoxicity (OIPN) is a high-incidence and dose-dependent adverse reaction during OXA treatment. Its underlying mechanisms remain unclear, and no effective treatment or prevention therapies are currently available. Here, we employed a data independent acquisition (DIA)-based quantitative proteomic strategy to investigate the global proteome alterations in the dorsal root ganglion (DRG) tissues from mice injected with OXA for different periods. We identified 1128 differentially regulated proteins that were divided into six subclusters according to their alteration trends. Interestingly, these proteins were involved in cellular processes such as cell cycle, ribosomal stress, metabolism, and ion transport. In addition, OXA administration induced abundance changes of ion channels and proteins associated with mitochondrial function and reactive oxygen species production. Furthermore, we investigated the effects of diroximel fumarate (DRF), an FDA-approved oral fumarate drug for the treatment of relapsing forms of multiple sclerosis. Our findings showed that DRF could effectively ameliorate symptoms of OIPN and reduce the level of oxidative stress in mice. Taken together, our study systematically mapped the proteome alteration associated with the neural toxicity of OXA, and the findings could be leveraged to better understand the mechanisms of OIPN and to develop more effect treatment therapies. SIGNIFICANCE: Oxaliplatin (OXA)-induced peripheral neurotoxicity (OIPN) is a high-incidence and dose-dependent adverse reaction with unclear mechanism. Here we employed a data independent acquisition (DIA)-based quantitative proteomic strategy to explore the proteome changes in dorsal root ganglion (DRG) tissues from mice treated by OXA. The findings provided novel insights regarding the mechanisms of OIPN. For example, our data showed that OXA induced a broad disturbance in metabolism, particularly in glycolysis and amino acid metabolism. Additionally, we observed abundance changes of many ion channels and proteins associated with mitochondrial function and reactive oxygen species production. Furthermore, this study provided the first evidence for the possibility of repositioning diroximel fumarate (DRF) for treating OIPN.

Nanoscale Covalent Organic Frameworks with Donor-Acceptor Structures as Highly Efficient Light-Responsive Oxidase-like Mimics for Colorimetric Detection of Glutathione.

Although organic artificial enzymes have been reported as biomimetic oxidation catalysts and are widely used for colorimetric biosensors, developing organic artificial enzymes with high enzymatic activity is still a challenge. Two-dimensional (2D) covalent organic frameworks (COFs) have shown superior potential in biocatalysts because of their periodic π-π arrays, tunable pore size and structure, large surface area, and thermal stability. The interconnection of electron acceptor and donor building blocks in the 2D conjugated COF skeleton can lead to narrower band gaps and efficient charge separation and transportation and thus is helpful to improve catalytic activity. Herein, a donor-acceptor 2D COF was synthesized using tetrakis(4-aminophenyl)pyrene (Py) as an electron donor and thieno[3,2-b]thiophene-2,5-dicarbaldehyde (TT) as an electron acceptor. Under visible light irradiation, the donor-acceptor 2D COF exhibited superior enzymatic catalytic activity, which could catalyze the oxidation of chromogenic substrates such as 3,3',5,5'-tetramethylbenzidine (TMB) by the formation of superoxide radicals and holes. Based on the above property, the photoactivated donor-acceptor 2D COF with enzyme-like catalytic properties was designed as a robust colorimetric probe for cheap, highly sensitive, and rapid colorimetric detection of glutathione (GSH); the corresponding linear range of GSH was 0.4-60 µM, and the limit of detection was 0.225 µM. This study not only presents the construction of COF-based light-activated nanozymes for environmentally friendly colorimetric detection of GSH but also provides a smart strategy for improving nanozyme activity.

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). The as-prepared sponges@COFs possessed many superior properties, including superhydrophobicity with the water contact angle of approximately 154.3°, large specific surface area (153.059 m2/g), high porosity of the network structures, as well as good mechanical and chemical stability. Taking the aformentioned advantages together, the superhydrophobic sponges showed ultra-high adsorption capacity for oil and various organic solvents. In comparision with its own weight, the adsorption amount of the sponges@COFs for silicone oil was up to 150 times and for toluene was 125 times, respectively. Furthermore, the superhydrophobic sponges also showed fast and highly efficient oil-water separation, outstanding flame retardancy and recyclability. In addition, the sponges@COFs were successfully applied to the high-efficiency removal of oil suspension from industrial waste water, firmly confirming their application prospect in industrial wastewater treatment.

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. The results showed that the trypsin-immobilized monolithic enzyme microreactor had much higher tryptic digestion efficiency than the free trypsin in solution, where the coverage of peptide sequences by mass spectrometry (MS)-based analysis could bear comparison with the free one, while the digestion time was dramatically shortened from 12 h to 16 s. Furthermore, the trypsin-immobilized monolithic enzyme microreactor also exhibited good practicability to complex human serum sample, in which the total of 45 peptides from human serum albumin (HSA) matched with sequence coverage of 75% were precisely identified. The successful application demonstrated the promising potential of the trypsin-immobilized capillary monolithic column as the IMER in high-throughput proteomic analysis.

Derivatization strategy combined with parallel reaction monitoring for the characterization of short-chain fatty acids and their hydroxylated derivatives in mouse.

Short-chain fatty acids (SCFAs) and hydroxylated short-chain fatty acids (OH-SCFAs) are crucial intermediates related to a variety of diseases, such as bowel disease, cardiovascular disease, renal disease and cancer. A global profiling method to screen SCFAs and OH-SCFAs was developed by tagging these analytes with d0/d6-N, N-dimethyl-6,7-dihydro-5H-pyrrolo [3,4-d] pyrimidine-2-amine (d0/d6-DHPP) and using ultra-high performance liquid chromatography coupled with high-resolution tandem mass spectrometry (UHPLC-MS/MS) in parallel reaction monitoring (PRM) mode. The derivatization procedure was simple and rapid. The targeted compounds could be derivatized within 3 min under mild condition and analyzed without the need of further purification. The derivatization significantly improved the chromatographic performance and mass spectrometry response. The d6-DHPP tagged standards were used as internal standards, which remarkably reduced the matrix effects. The use of high resolution PRM mode made it possible to locate unknown SCFA and OH-SCFA species, and greatly reduced the false positive identification results. The developed method was successfully applied to the analysis of mouse fecal, serum, and liver tissue samples harvested from the breast cancer nude mice that had been exposed with 2,2',4,4'-tetrabromodiphenyl ether (BDE-47). Results showed that 40 analytes (10 SCFAs and 30 OH-SCFAs) were characterized. Semi-quantitative analysis indicated that the exposure of BDE-47 to the mice altered the SCFA and OH-SCFA metabolism, especially in the high dose group. This study provides a high-throughput method to characterize SCFAs and OH-SCFAs in mouse samples.

Facile synthesis of magnetic covalent organic framework nanobeads and application to magnetic solid-phase extraction of trace estrogens from human urine.

A rapid and facile approach was developed for the synthesis of core-shell structured magnetic covalent organic framework nanobeads by using the monodisperse Fe3O4 nanoparticles (NPs) as magnetic core, and 1,3,5-triformylbenzene (Tb) and benzidine (Bd) as two building blocks (denoted as Fe3O4@TbBd), which were explored as an adsorbent for magnetic solid-phase extraction (MSPE) of estrogens from human urine sample. The core-shell structured Fe3O4@TbBd nanobeads showed some attractive features involving high specific surface area (202.18 m2/g), uniform pore size distribution (2.8 nm), high magnetic responsivity (41.4 emu/g), as well as excellent thermal and chemical stability, which made it an ideal adsorbent for selective isolation and enrichment of estrogens. Some parameters influencing extraction efficiency, including adsorbent dosage, extraction time, pH, ion strength, desorption solvent and desorption time were investigated systematically. Combined with HPLC-MS, a simple, fast, and sensitive method was developed for the enrichment and sensitive determination of seven estrogens, which showed good linearity (r > 0.9978) in the range of 0.005-10 µg/L, low limits of detection (0.2-7.7 ng/L, S/N = 3), low limits of quantification (0.6-25.6 ng/L, S/N = 10), high enrichment factors (75-197 fold), and good precision with relative standard deviations (RSD) lower than 4.8% for intra-day and 6.7% for inter-day. The proposed method was successfully applied to the analysis of trace estrogens in urine sample of pregnant woman with good recoveries (80.6-111.6%), demonstrating the promising potential of the Fe3O4@TbBd nanobeads as adsorbent in sample pretreatment.

CuFe2O4 magnetic nanocrystal clusters as a matrix for the analysis of small molecules by negative-ion matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

CuFe2O4 magnetic nanocrystal clusters (CuFe2O4 MNCs) were proposed as a new matrix for small molecule analysis by negative ion matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for the first time. We demonstrated its advantages over conventional organic matrices in the detection of small molecules such as amino acids, peptides, nucleobases, fatty acids, and steroid hormones. A systematic comparison of CuFe2O4 MNCs with different ionization modes revealed that MS spectra obtained for the CuFe2O4 MNC matrix in the negative ion mode was only featured by deprotonated ion peaks with a free matrix background, which was different from the complicated alkali metal adducts produced in the positive ion mode. The developed method was found relatively tolerant to salt contamination and exhibited good reproducibility. A detection limit down to the subpicomolar level was achieved when testosterone was analyzed. In addition, by comparison of the MS spectra obtained from bare Fe3O4 and MFe2O4 MNC (M = Co, Ni, Cu, Zn) matrices, two main factors of MFe2O4 MNC matrices were revealed to play a vital role in assisting the negative ion desorption/ionization (D/I) process: doping transition metals into ferrite nanocrystals favoring laser absorption and energy transfer and a good match between the UV absorption of MFe2O4 MNCs and the excitation of nitrogen laser source facilitating LDI efficiency. This work creates a new branch of application for MFe2O4 MNCs and provides an alternative solution for small molecule analysis.

Incorporation of graphene oxide nanosheets into boronate-functionalized polymeric monolith to enhance the electrochromatographic separation of small molecules.

Graphene oxide (GO) nanosheets were incorporated into an organic polymer monolith containing 3-acrylamidophenylboronic acid (AAPBA) and pentaerythritol triacrylate (PETA) to form a novel monolithic stationary phase for CEC. The effects of the mass ratio of AAPBA/PETA, the amount of GO, and the volume of porogen on the morphology, permeability and pore properties of the prepared poly(AAPBA-GO-PETA) monoliths were investigated. A series of test compounds including amides, alkylbenzenes, polycyclic aromatics, phenols, and anilines were used to evaluate and compare the separation performances of the poly(AAPBA-GO-PETA) and the parent poly(AAPBA-co-PETA) monoliths. The results indicated that incorporation of GO into monolithic column exhibited much higher resolutions (>1.5) and column efficiency (62,000 ∼ 110,000 plates/m for toluene, DMF, formamide, and thiourea) than the poly(AAPBA-co-PETA). The successful application in isocratic separation of peptides suggests the potential of the GO incorporated monolithic column in complex sample analysis. In addition, the reproducibility and stability of the prepared poly(AAPBA-GO-PETA) monolith was assessed. The run-to-run, column-to-column and batch-to-batch reproducibilities of this monolith for alkylbenzenes' retention were satisfactory with the RSDs less than 1.8% (n = 5), 3.7% and 5.6% (n = 3), respectively, indicating the effectiveness and practicability of the proposed method.

One-pot preparation of glutathione-silica hybrid monolith for mixed-mode capillary liquid chromatography based on "thiol-ene" click chemistry.

A novel glutathione (GSH)-silica hybrid monolithic column synthesized via a combination of thiol-ene click reaction and one-pot process was described, where thiol-end GSH organic monomer and 2,2-azobisisobutyronitrile (AIBN) were mixed with hydrolyzed tetramethyloxysilane (TMOS) and γ-methacryloxypropyltrimethoxysilane (γ-MAPS) and then introduced into a fused-silica capillary for simultaneous polycondensation and "thiol-ene" click reaction to form the GSH-silica hybrid monolith. The effects of the molar ratio of TMOS/γ-MAPS, the amount of GSH, and the volume of porogen on the morphology, permeability and pore properties of the prepared GSH-silica hybrid monoliths were studied in detail. A uniform monolithic network with high porosity was obtained. A series of test compounds including alkylbenzenes, amides, and anilines were used to evaluate the retention behaviors of the GSH-silica hybrid monolithic column. The results demonstrated that the prepared GSH-silica hybrid monolith exhibited multiple interactions including hydrophobicity, hydrophilicity, as well as cation exchange interaction. The run-to-run, column-to-column and batch-to-batch reproducibilities of the GSH-silica hybrid monolith for phenols' retention were satisfactory with the relative standard deviations (RSDs) less than 1.3% (n=5), 2.6% (n=3) and 3.2% (n=3), respectively, indicating the effectiveness and practicability of the proposed method. In addition, the GSH-silica hybrid monolith was applied to the separation of nucleotides, peptides and protein tryptic digests, respectively. The successful applications suggested the potential of the GSH-silica hybrid monolith in complex sample analysis.

Polymer monolithic capillary column fabricated by using monodisperse iron oxide nanocrystal template to enhance the electrochromatographic separation of small molecules.

Monodisperse iron oxide nanocrystals and organic solvents were utilized as coporogens in monolithic poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) capillary columns to afford stationary phases with enhanced electrochromatographic performance of small molecules. While the conventional monoliths using organic solvents only as a porogen exhibited poor resolution (Rs) <1.0 and low efficiency of 40 000-60 000 plates/m, addition of a small amount of nanocrystals to the polymerization mixture provided increased resolution (Rs > 3.0) and high efficiency ranged from 60 000 to 100 000 plates/m at the same linear velocity of 0.856 mm/s. It was considered that the mesopores introduced by the nanocrystals played an important role in the improvement of the monolith performance. This new strategy expanded the application range of the hydrophobic monoliths in the separation of polar alkaloids and narcotics. The successful applications demonstrated that the glycidyl methacrylate based monoliths prepared by using nanocrystal template are a good alternative for enhanced separation efficiency of small molecules.

An improved hollow fiber solvent-stir bar microextraction for the preconcentration of anabolic steroids in biological matrix with determination by gas chromatography-mass spectrometry.

In this paper, a convenient and self-assembled hollow fiber solvent-stir bar microextraction (HF-SSBME) device was developed, which could stir by itself. In the extraction process, the proposed device made the solvent "bar" not floating at the sample solution and exposing to air while organic solvents outside hollow fiber always wrapped with donor phase solvent, which reduced the vaporization of organic solvents. This design could improve the precisions and recoveries of experiments. For evaluating the device, seven anabolic steroids (prasterone, 5α-androstane-3α, 17ß-diol, methandriol, 19-norandrostenediol, androstenediol, methyltestosterone and methandienone) were used as model analytes and extraction conditions such as type and volume of organic solvents, agitation speed, extraction time, extraction temperature and salt addition were studied in detail. Under the optimum conditions (15 µL toluene, 40 °C, stirring at 750 rpm for 30 min with 1.5 g sodium chloride addition in 20.0 mL donor phase), the linear ranges of anabolic steroids were 0.25-200 ng mL(-1) with gas chromatography-mass spectrometry. The limits of detection were lower than 0.10 ng mL(-1). The recoveries and precisions in spiked urine and hair samples were between 73.97-93.56% and 2.18-4.47% (n=5). HF-SSBME method combined the intrinsical merits of hollow fiber with the superiority of the proposed self-stirring device which can be developed to two-phase, three-phase and in situ derivatization modes with wide prospect of application. Besides, the pedestal of this proposed device can be converted to fix stir bar in stir bar sorptive extraction (SBSE) method.

Monolithic column based on a poly(glycidyl methacrylate-co-4-vinylphenylboronic acid-co-ethylene dimethacrylate) copolymer for capillary liquid chromatography of small molecules and proteins.

A new polymer monolith with three modes of reverse-phase, hydrophilic and cation-exchange interaction was synthesized in 100 µm i.d. fused-silica capillary by in situ polymerization procedure. The pre-polymerization mixture consisted of glycidyl methacrylate (GMA) and 4-vinylphenylboronic acid (VPBA) as bifunctional monomers, ethylene dimethacrylate (EDMA) as crosslinker, 1,4-butanediol (BDO) and diethylene glycol (DEG) as binary porogenic solvents, and azobisisobutyronitrile (AIBN) as initiator. The resulting poly(GMA-co-VPBA-co-EDMA) monolith showed a relatively homogeneous monolithic structure, good permeability and mechanical stability. Different ratios of monomers and porogens were used for optimizing the properties of monolithic column. The column performance was assessed by the separation of a series of neutral solutes, charge solutes, phenols and anilines. Compared with poly(GMA-co-EDMA) monolith, the proposed monolith exhibited more flexible adjustment of selectivity in terms of hydrophobic, hydrophilic, as well as cation-exchange interaction in the same chromatographic conditions. High column efficiencies for benzene derivatives with 70,000-102,000 theoretical plates/m could be obtained at a linear velocity of 0.265 mm/s. The run-to-run, column-to-column, and batch-to-batch repeatabilities of the retention times were less than 8.23%. Additionally, the purposed monolith was also applied to efficient separation of alkaloids and proteins for demonstrating its potential in biomolecule separation.

Analysis of plant hormones by microemulsion electrokinetic capillary chromatography coupled with on-line large volume sample stacking.

A novel method of microemulsion electrokinetic capillary chromatography (MEEKC) coupled with on-line large volume sample stacking was developed for the analysis of six plant hormones including indole-3-acetic acid, indole-3-butyric acid, indole-3-propionic acid, 1-naphthaleneacetic acid, abscisic acid and salicylic acid. Baseline separation of six plant hormones was achieved within 10 min by using the microemulsion background electrolyte containing a 97.2% (w/w) 10 mM borate buffer at pH 9.2, 1.0% (w/w) ethyl acetate as oil droplets, 0.6% (w/w) sodium dodecyl sulphate as surfactant and 1.2% (w/w) 1-butanol as cosurfactant. In addition, an on-line concentration method based on a large volume sample stacking technique and multiple wavelength detection was adopted for improving the detection sensitivity in order to determine trace level hormones in a real sample. The optimal method provided about 50-100 fold increase in detection sensitivity compared with a single MEEKC method, and the detection limits (S/N = 3) were between 0.005 and 0.02 µg mL(-1). The proposed method was simple, rapid and sensitive and could be applied to the determination of six plant hormones in spiked water samples, tobacco leaves and 1-naphthylacetic acid in leaf fertilizer. The recoveries ranged from 76.0% to 119.1%, and good reproducibilities were obtained with relative standard deviations (RSDs) less than 6.6%.