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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. Source

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. Source

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. Source

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. Source

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. Source

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