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Rong M.,Xiamen University | Lin L.,Xiamen University | Song X.,Xiamen University | Zhao T.,Xiamen Huaxia Vocational College | And 4 more authors.
Analytical Chemistry | Year: 2015

An effective and facile fluorescence sensing approach for the determination of 2,4,6-trinitrophenol (TNP) using the chemically oxidized and liquid exfoliated graphitic carbon nitride (g-C3N4) nanosheets was developed. The strong inner filter effect and molecular interactions (electrostatic, π- π, and hydrogen bonding interactions) between TNP and the g-C3N4 nanosheets led to the fluorescence quenching of the g-C3N4 nanosheets with efficient selectivity and sensitivity. Under optimal conditions, the limit of detection for TNP was found to be 8.2 nM. The proposed approach has potential application for visual detection of TNP in natural water samples for public safety and security. © 2014 American Chemical Society.


Chen X.,Xiamen University | Cai Z.-M.,Xiamen University | Wu Y.-F.,Xiamen University | Huang Y.-H.,Xiamen University | And 2 more authors.
Talanta | Year: 2012

Chitosan, a cationic polysaccharide containing amino and hydroxyl groups, was used to fabricate an electrochemiluminescence (ECL) sensor. In the sensor construction, a glassy carbon electrode (GCE) was first coated by a chitosan film which embedded gold nanoparticles, and then the film was modified by introducing carboxyl groups on the surface, which were used to immobilize tris(2,2′-bipyridyl)ruthenium(II) doped amino-functional silica nanoparticles (NH 2-RuSiNPs) through amido links. The successful modification was confirmed by scanning electronic microscopy and cyclic voltammetry. A binding model between the chitosan/nanogold composite film and NH 2-RuSiNPs was also proposed, in which the amido link was the dominant bonding, accompanied with hydrogen bond interaction. ECL studies revealed that the sensor had very good response to different concentrations of 2-(dibutylamino) ethanol. This sensor was also applied in methamphetamine determination. © 2012 Elsevier B.V. All rights reserved.


Liao S.,Fuzhou University | Liao S.,Wuyi University | Wang X.,Fuzhou University | Lin X.,Fuzhou University | And 2 more authors.
Electrophoresis | Year: 2010

A polymethacrylate-based molecularly imprinted monolithic column bearing mixed functional monomers, using non-covalent imprinting approach, was designed for the rapid separation of nitroimidazole compounds. The new monolithic column has been prepared via simple in situ polymerization of 2-hydroxyethyl methacrylate, dimethyl-aminoethyl methacrylate and ethylene dimethacrylate, using (S)-ornidazole ((S)-ONZ) as template in a binary porogenic mixture consisting of toluene and dodecanol. The composition of the polymerization mixture was systematically altered and optimized by altering the amount of monomers as well as the composition of the porogenic solvent. The column performance was evaluated in pressure-assisted CEC mode. Separation conditions such as pH, voltage, amount of organic modifier and salt concentration were studied. The optimized monolithic column resulted in excellent separation of a group of structurally related nitroimidazole drugs within 10 min in isocratic elution condition. Column efficiencies of 99 000, 80 000, 103 000, 60 000 and 99 000 plates/m were obtained for metronidazole, secnidazole, ronidazole, tinidazole and dimetridazole, respectively. Parallel experiments were carried out using molecularly imprinted and non-imprinted capillary columns. The separation might be the result of combined effects including hydrophobic, hydrogen bonding and the imprinting cavities on the (S)-ONZ-imprinted monolithic column. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.


Chen X.,Xiamen University | Wu G.-H.,Xiamen University | Jiang Y.-Q.,Xiamen University | Wang Y.-R.,Xiamen University | And 2 more authors.
Analyst | Year: 2011

Similar to its popular older cousins of fullerene and carbon nanotubes (CNTs), the latest form of nanocarbon, graphene, is inspiring intensive research efforts in its own right. As an atomically thin layer of sp 2- hybridized carbon, graphene possesses spectacular electronic, optical, magnetic, thermal and mechanical properties, which make it an exciting material in a variety of important applications. In this review, we present the current advances in the field of graphene electroanalytical chemistry, including the modern methods of graphene production, and graphene functionalization. Electrochemical (bio) sensing developments using graphene and graphene-based materials are summarized in more detail, and we also speculate on their future and discuss potential progress for their applications in electroanalytical chemistry. © 2011 The Royal Society of Chemistry.


Lin J.,Fuzhou University | Liu S.,CAS Zhengzhou Research Institute | Lin X.,Fuzhou University | Xie Z.,Fuzhou University | Xie Z.,Xiamen Huaxia Vocational College
Journal of Chromatography A | Year: 2011

A novel highly hydrophilic polymethacrylate-based monolithic stationary phase based on the copolymerization of 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and pentaerythritol triacrylate (PETA) was designed for pressurized capillary electrochromatography. A typical hydrophilic interaction chromatography mechanism could be observed when the content of acetonitrile (ACN) in the mobile phase exceeded 25%. Slight swelling or shrinking with mobile phases of different polarity was observed in permeability studies. Good retentions and efficient separations of polar analytes, such as neutral amides and phenols, were well achieved in hydrophilic interaction chromatography mode with only about 50% ACN content in the mobile phase. It was remarkably lower than the content of ACN (>90%) used on the hydrophilic polymethacrylate-based monoliths reported previously. Additionally, a mixed mode of hydrophilic interaction (HI) and strong cation-exchange (SCX) could be also obtained in the analysis of charged peptides, and high column efficiency up to 80,000. plates/m was achieved without peak tailing. The prepared hydrophilic stationary phase might provide a potential environmental friendly separation media for polar solutes as it consumes a low volume of organic solvents. © 2011 Elsevier B.V.


Lin X.,Fuzhou University | Li Y.,Fuzhou University | Xu D.,Fuzhou University | Yang C.,Fuzhou University | And 2 more authors.
Analyst | Year: 2013

An improved hydrophilic interaction/strong anion-exchange (HI-SAX) monolith for rapid capillary electrochromatographic profiling has been developed to detect carboxylic phytohormones with high resolution. The HI-SAX monolith was prepared by copolymerization of 2-(methacryloyloxy)ethyltrimethylammonium methyl sulfate, pentaerythritol triacrylate and porogenic solvents. Detailed polymerization compositions were investigated and improved, and the characteristics in terms of morphology, retention mechanism and column reproducibility were studied. A typical hydrophilic chromatography mechanism was observed when ACN content exceeded 30%, and the HI-SAX mixed-mode was verified with nucleic acid bases and nucleosides. Based on the improved HI-SAX monolith, capillary electrochromatographic profiling of typical phytohormones was evaluated by using indole-3-acetic acid (IAA), abscisic acid (ABA) and gibberellic acid (GA3) as the mode analytes. Effects of the test parameters on carboxyl phytohormones were investigated, and a fast analysis with high resolution for the representative phytohormones was achieved within 4.0 min with intraday RSDs (n = 3) less than 2.6% and 6.3% for the retention time and peak area, respectively. When applied to spiked corn samples, mean recoveries between 82.3% and 95.4% were obtained. © 2013 The Royal Society of Chemistry.


Wang X.,Fuzhou University | Zheng N.,Fuzhou University | Huang Y.,Fuzhou University | Wang J.,Fuzhou University | And 3 more authors.
Electrophoresis | Year: 2013

A pyridinium-based immobilized ionic liquid type multifunctional hybrid silica monolith was prepared by the in situ polymerization of 3-chloropropyl-silica matrix and 4,4′-dipyridyl for hydrophilic interaction CEC. The obtained hybrid monolith possessed of high stable skeletal microstructures with obviously hydrophilic retention mechanism under ACN content >50% in the mobile phase. Strong and stable anodic EOF could be observed under a broad pH range from pH 3.0 to 9.0. Due to the immobilized dipyridyl groups bonded to the silica matrix surface, the resulting hydrophilic hybrid monolith possessed multiple separation interactions including hydrogen bond, π-π, and anion exchange. Excellent separations of various polar analytes including electroneutral phenols, charged acid nucleotides, and basic analytes were successfully achieved. The highest column efficiencies up to 120000, 164000, and 106000 plates/m were obtained for nucleotides, nucleic acid bases, and nucleosides and nicotines, respectively. These results demonstrated that the dipyridyl-immobilized ionic liquid functionalized hybrid monolith possessed highly mechanical stability and good chromatographic performance for hydrophilic interaction electrochromatography. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Wang X.,Fuzhou University | Zheng Y.,Fuzhou University | Zhang C.,Fuzhou University | Yang Y.,Fuzhou University | And 4 more authors.
Journal of Chromatography A | Year: 2012

A novel organic-silica hybrid monolithic stationary phase with a mixed-mode of hydrophilic and strong anion-exchange interactions (HI-SAX) was prepared with a modified " one-pot" process of functional monomers and alkoxysilanes. Using a hydrosoluble initiator 2,2'-azobis(2-methylpropionamidine) dihydrochloride (AIBA), the homogeneous prepolymerization system of this hybrid monolith was successfully obtained by a simple operation. The polycondensation of alkoxysilanes (tetramethoxysilane (TMOS) and vinyl-trimethoxysilane (VTMS)) and the in situ copolymerization of a quaternary ammonium group-containing acrylic monomer ([2-(acryloyloxy)ethyl] trimethyl ammonium methyl sulfate (AETA)) on the precondensed siloxanes were achieved. The morphologies of the hybrid-silica monolithic matrixes were observed by SEM, and the performances of the organic-silica hybrid monolithic columns were investigated by pressurized capillary electrochromatography. The mechanical stability and reproducibility of the obtained hybrid monolithic column preformed acceptable. Both hydrophilic interaction chromatography mechanism and strong anion-exchanged interaction were investigated. A mixed mode of HI-SAX was obtained for the analysis of nucleotides with a good resolution, and the separation of polar and basic nucleic acid bases and nucleosides was also achieved without peak tailing. © 2012 Elsevier B.V..


Zhu C.-L.,Fuzhou University | Wang X.-W.,Fuzhou University | Lin Z.-Z.,Fuzhou University | Xie Z.-H.,Fuzhou University | Wang X.-R.,Xiamen Huaxia Vocational College
Journal of Food and Drug Analysis | Year: 2014

To develop novel tumor cell microenvironment stimuli-responsive smart controlled-release delivery systems is one of the current common interests of materials science and clinical medicine. Meanwhile, mesoporous silica nanoparticles as a promising drug carrier have become the new area of interest in the field of biomedical application in recent years because of their unique characteristics and abilities to efficiently and specifically entrap cargo molecules. This review describes the more recent developments and achievements of mesoporous silica nanoparticles in drug delivery. In particular, we focus on the stimuli-responsive controlled-release systems that are able to respond to tumor cell environmental changes, such as pH, glucose, adenosine-50-triphosphate (ATP), glutathione (GSH), and H2O2. Copyright © 2014, Food and Drug Administration, Taiwan. Published by Elsevier Taiwan LLC. All rights reserved.Grant: Acknowledgments: Financial support from the National Natural Science Foundation of China (NSFC 21001033, 21271044), the NSF of Fujian (2011J01039), and Research Foundation for Talented Scholars in Fu Zhou University (022330) is greatly acknowledged.


Su B.,Centers for Disease Control and Prevention | Wu G.,Xiamen University | Yang C.J.,Xiamen University | Zhuang Z.,Xiamen Huaxia Vocational College | And 4 more authors.
Journal of Materials Chemistry | Year: 2012

This paper reports a nontoxic, rapid, one-pot and template-free synthesis of three-dimensional (3D) Pt nanoflowers (PtNFs) with high yield and good size monodispersity supported on graphene oxide (GO) nanosheets. The key synthesis strategy employed a low-cost, green solvent, ethanol as the reductant and an advanced, powerful 2D carbon material, GO nanosheets as the stabilizing material. The resulting PtNFs-GO nanosheets were characterized by transmission electron microscopy (TEM), high-resolution TEM, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and electrochemical techniques. It was found that the monodispersed, porous PtNFs supported on GO nanosheets were a uniform size of 30 nm and each was composed of numerous "clean" and small (4 nm) Pt nanoparticles, which revealed an unusually high activity for methanol oxidation reaction compared to commercial Pt black. Furthermore, based on a systematic study of the PtNFs growth conditions, a possible mechanism, and especially the importance of GO in the formation was proposed. Our study demonstrates that GO is a promising support material for developing next-generation advanced Pt based fuel cells and their relevant electrodes in the field of energy. © 2012 The Royal Society of Chemistry.

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