EUROPEAN FOOD RESEARCH AND TECHNOLOGY
·
2014
·Vol. 238
·期 5
·889-894
·
IF 1.387
Zhu Jinghui,Li Chunyan,Liu Shaopu,Liu Zhongfang,Yang Jidong,Tian Jing,Hu Xiaoli
A non-diazotization-coupling reaction-based colorimetric method was developed and validated for the determination of nitrite in tap water and milk samples. Under acidic condition, nitrite could selectively react with pyrrole, resulting in the emerging of a new absorption peak at 509 nm and a distinct color change from clear to red, with which the concentration of nitrite can be determined indirectly. Excellent linear range was achieved from 0.72 to 40.0 μmol L −1 with a detection limit of 0.22 μmol L −1 . The detection limit was lower than or comparable to most of the recently published methods. The experimental conditions were optimized, and effects of coexisting substances were evaluated, and the results showed excellent priority since a certain amount of other anions, including SO 3
− , SeO 3
− and other acid radicals, would not interfere with the measurement. We highlighted the simplicity and efficiency of this method as no diazotization-coupling procedure and toxic aniline were involved. Determination of nitrite in tap water and milk samples was performed.
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ELECTROCHIMICA ACTA
·
2014
·
IF 4.086
Lihuan Xu,Fang Yang,Chang Su,Lvlv Ji,Cheng Zhang
Two 2,2,6,6-tetramethylpiperidinyl-N-oxy (TEMPO) contained polypyrrole (PPy) derivatives with the different side-chain length were synthesized by esterification of 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl free radial with pyrrole butyric acid and pyrrole caproic acid. Then the homopolymers of 4-(3-(Pyrrol-1-yl)butyryloxy)-2,2,6,6-tetramethylpiperidin-1-yloxy (PPy-B-TEMPO) and 4-(3-(Pyrrol-1-yl)hexanoyloxy)-2,2,6,6-tetramethylpiperidin-1-yloxy (PPy-C-TEMPO) were prepared by chemical oxidative polymerization. The structure, morphology, electrochemical properties of prepared polymers were characterized by fourier transform infrared spectroscopy (FTIR), ultraviolet visible spectroscopy (UV-vis), scanning electron microscopy (SEM), cyclic voltammograms (CV) and electrochemical impedance spectra (EIS), respectively. Also, the charge-discharge properties of the prepared polymers were studied by galvanostatic charge-discharge testing. The results demonstrated that the as-synthesized nitroxide radical polymers showed a reversible two-electron redox reaction process in the potential limits of 2.5–3.0 V and 3.4–3.8 V vs Li/Li + , respectively. Under our experimental conditions, PPy only presented the discharge capacity of 16.5 mAh·g −1 at 20 mA·g −1 between 2.5 and 4.2 V, while PPy-B-TEMPO with the short side-chain linked to TEMPO groups exhibited an initial discharge capacity of up to 86.5 mAh·g −1 with two well-defined plateaus. Furthermore, the PPy-C-TEMPO with the longer linking side-chain even displayed a discharge capacity of 115 mAh·g −1 . These superior electrochemical performances were ascribed to the flexible linking side-chain and the introduction of stable conductive PPy main chain, which benefits the improvement of charge carrier transportation in the aggregated polymer bulk.
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BIOPOLYMERS
·
2013
·Vol. 101
·期 5
·496-503
·
IF 2.879
Zhihong Zhang,Shunli Liu,Yu Shi,Jun Dou,Shaoming Fang
This study investigates the application of Plasma-polymerized pyrrole (ppPY) as bioactive platform for DNA immobilization and cell adhesion based on the fundamental properties of ppPY, such as chemical structure, electrochemical property, and protein adsorption. Variations in electrochemical properties of the ppPY film deposited under different plasma conditions before and after DNA immobilization were measured using electrochemical impedance spectroscopy (EIS). The equilibrium concentration of the probe DNA immobilized on the ppPY surface was deduced by detecting the variations in the surface charge transfer resistance ( R ct ) of the ppPY films after DNA immobilization with different concentrations. In addition, the detection limit of the target DNA hybridization with probe DNA, the association constant, K a , and the dissociation constant were deduced from Langmuir isotherm equations simulated using the experimental data collected by EIS. Moreover, inverted microscope was used to observe the cell adhesions onto the surface of the ppPY films prepared under different plasma conditions. Different adhesive behaviors of cells were observed, demonstrating that ppPY films could be an alternative biomaterial used as the sensitive layer for DNA sensor or cell adhesion. © 2013 Wiley Periodicals, Inc. Biopolymers 101: 496–503, 2014.
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SYNTHETIC METALS
·
2015
·
IF 2.252
Haihan Zhou,Gaoyi Han,Yaoming Xiao,Yunzhen Chang,Hua-Jin Zhai
Polypyrrole/poly(sodium 4-styrenesulfonate)-carbon nanotubes (PPy/PSS-CNT) nanocomposites have been fabricated with an in situ electrochemically polymerized method. The long (10–30 μm) and short (0.5–2 μm) CNT are incorporated separately into the composites, and their effect on the capacitive performance of composites prepared is compared. Scanning electron microscope characterization reveals that long CNT-incorporated composites (PPy/PSS-lCNT) have the more porous microstructure and present a large amount of CNT within the composites, in which these long tangled CNT form an interconnected conductive nano-network. Furthermore, combining with the transmission electron microscopy characterization, both of the two types of composites show the core–shell nanostructure with PPy layer coated on CNT. The results by electrochemical tests including cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrochemical impedance spectroscopy (EIS) manifest the PPy/PSS-lCNT composite electrodes have the relatively more superior capacitive behavior and cycle stability than those of the short CNT-incorporated composites (PPy/PSS-sCNT) electrodes. Thereinto, the PPy/PSS-lCNT composite electrodes exhibit a high areal capacitance of 146.1 mF cm −2 at 10 mV s −1 CV scan, retaining 94.0% of the initial capacitance after 5000CV cycles. This comparative study suggests that the long CNT-incorporated PPy/PSS-lCNT nanocomposites are relatively more promising as the electrode materials for the high-performance supercapacitors.
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RSC Advances
·
2015
·Vol. 5
·期 13
·9848-9851
·
IF 3.84
Meng Lin
A novel sensor based on a gold nanoparticles (Au NPs)/over-oxidized polypyrrole (OPPy) nanotube (NT) composite arrays electrode proved to be highly effective for electrochemical determination of dopamine (DA). Oriented Au NPs/OPPy NT arrays were electrodeposited by using zinc oxide (ZnO) nanowire (NW) arrays as templates. The morphologies of ZnO NW arrays, OPPy NT arrays, and Au NPs/OPPy NT arrays were studied by scanning electron microscopy (SEM). Electrochemical behaviors of the modified electrodes were characterized by cyclic voltammetry (CV) and square wave voltammetry (SWV) techniques. The Au NPs/OPPy NT arrays electrode had strong catalytic activity toward the oxidation of DA. The peak currents obtained from SWV increased linearly with increasing DA concentrations in the range of 25 nM to 2.5 μM. The simultaneous analysis of ascorbic acid (AA) and DA was investigated, the results demonstrated that the Au NPs/OPPy NT arrays electrodes exhibited good selectivity and sensitivity for the determination of DA without interference by the oxidation of AA.
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ANALYST
·
2013
·Vol. 138
·期 20
·5949-5955
·
IF 3.969
Min Cui,Su Liu,Wenjing Lian,Jie Li,Wei Xu,Jiadong Huang
In this study, we developed a novel molecularly-imprinted electrochemical sensor based on a glassy carbon electrode (GCE) decorated by graphene–Prussian blue (GR–PB) composites for the selective and sensitive determination of butylated hydroxyanisole (BHA). The molecularly-imprinted polymers (MIPs) were synthesized by BHA and pyrrole as the template molecule and functional monomer, respectively. Also, the MIPs were assembled on the surface of the GR–PB/GCE by electropolymerization. The sensor was characterized by cyclic voltammetry (CV), scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and chronoamperometry. It was confirmed that the synergistic effects of GR and PB could improve the electrochemical response and the sensitivity of the sensor. The linear range of the sensor was from 9 × 10−8 mol L−1 to 7 × 10−5 mol L−1, with a limit of detection (LOD) of 7.63 × 10−8 mol L−1 (S/N = 3). The proposed sensor displayed high selectivity, excellent stability and good reproducibility for the determination of BHA. It was successfully applied to the determination of BHA in real samples.
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高影响因子
Nanoscale
·
2013
·Vol. 5
·期 18
·8703-8710
·
IF 6.233
Fang Deng,Lujuan Min,Xubiao Luo,Shaolin Wu,Shenglian Luo
Conductive polypyrrole–polyaniline/TiO2 nanocomposites (PPy–PANI/TiO2) were prepared by in situ oxidative copolymerization of pyrrole and aniline monomers in the presence of TiO2. For comparison studies, polypyrrole/TiO2 (PPy/TiO2) and polyaniline/TiO2 (PANI/TiO2) were also prepared. The samples were characterized by X-ray diffraction, transmission electron microscopy, UV-vis diffuse reflectance spectroscopy, zeta potential analysis, Fourier transform infrared spectroscopy, thermogravimetric analysis and photocurrent tests. In contrast to PPy/TiO2 and PANI/TiO2, PPy–PANI/TiO2 exhibits obvious absorption in the visible-light range, and is much superior to PPy/TiO2 and PANI/TiO2 in thermal stability. It is found that PPy–PANI/TiO2 performs well in the visible-light photocatalytic degradation of 4-nitrophenol. The optimized pyrrole : aniline : TiO2 molar ratio for best performance is 0.75 : 0.25 : 100. The efficacy of PPy–PANI/TiO2 is attributed to its conductivity, conjugated structure, as well as to the synergy amidst polypyrrole, polyaniline and TiO2.
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Nanoscale
·
2013
·Vol. 5
·期 19
·9150-9155
·
IF 6.233
Yi Sui,Jinghai Liu,Yuewei Zhang,Xike Tian,Wei Chen
Developing new methods to improve the photocatalytic activity of graphitic carbon nitride (g-C3N4) for hydrogen (H2) evolution has attracted intensive research interests. Here, we report that the g-C3N4 exhibits photocatalytic activity for H2 evolution from pure water. And, the activity is dramatically improved by loading highly dispersed conductive polymer nanoparticles. The H2 evolution rate increases up to 50 times for g-C3N4 with 1.5 wt% polypyrrole (PPy) nanoparticles on the surface. The reaction proceeding in a pure water system excludes the need for sacrificial agents. The role of the highly conductive PPy in enhancing H2 evolution is as a surface junction to increase the number of photoinduced electrons, and to facilitate electron transfer to the interface.
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Journal of Environmental Chemical Engineering
·
2015
·
IF 0
Qianqian Xin,Jianwei Fu,Zhonghui Chen,Shujun Liu,Ya Yan,Jianan Zhang,Qun Xu
The polypyrrole (PPy) nanofibers were synthesized by an oxidative template assembly route and evaluated as an adsorbent for the removal of a typical anionic dye (methyl orange, MO) from aqueous solution. The as-synthesized PPy nanofibers were characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and N 2 sorption. The effects of contact time, initial MO concentration, temperature, and initial solution pH on the adsorption of MO onto PPy nanofibers have been investigated. Experimental results showed that the PPy nanofibers possessed excellent adsorption capacity for MO (169.55 mg/g) at 25 °C. The pseudo-second-order model could fit to the experimental data better comparing with the pseudo-first-order kinetic adsorption model. And isotherm data fitted well to the Langmuir isotherm model. Thermodynamic study revealed that the adsorption process was endothermic and spontaneous in nature. In addition, the possible adsorption mechanism was proposed based on the experimental results. And the selective adsorption behaviors of the polypyrrole nanofibers towards different organic dyes were explored and the re-use of adsorbate was tested.
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Nanoscale
·
2015
·Vol. 7
·期 17
·7682-7691
·
IF 7.394
Zhiyou Peng,Jinbao Qin,Bo Li,Kaichuang Ye,Yuxin Zhang,Xinrui Yang,Fukang Yuan,Lijia Huang,Junqing Hu,Xinwu Lu
Photothermal therapy (PTT), as a promising treatment for tumours, has rarely been reported for application in artery restenosis, which is a common complication of endovascular management due to enduring chronic inflammation and abnormal cell proliferation. In our study, biodegradable polypyrrole nanoparticles (PPy-NPs) were synthesized and characterized, including their size distribution, UV-vis-NIR absorbance, molar extinction coefficients, and photothermal properties. We then verified that PPy-NP incubation followed by 915 nm near-infrared (NIR) laser irradiation could effectively ablate inflammatory macrophages in vitro, leading to significant cell apoptosis and cell death. Further, it was found that a combination of local PPy-NP injection with 915 nm NIR laser irradiation could significantly alleviate arterial inflammation by eliminating infiltrating macrophages and further ameliorating artery stenosis in an ApoE−/− mouse model, without showing any obvious toxic side effects. Thus, we propose that PTT based on PPy-NPs as photothermal agents and a 915 nm NIR laser as a power source can serve as a new effective treatment for reducing inflammation and stenosis formation in inflamed arteries after endovascular management.
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ANALYTICA CHIMICA ACTA
·
2015
·
IF 4.513
Wanying Zhu,Guoyi Jiang,Lei Xu,Bingzhi Li,Qizhi Cai,Huijun Jiang,Xuemin Zhou
Based on magnetic field directed self-assembly (MDSA) of the ternary Fe 3 O 4 @PANI/rGO nanocomposites, a facile and controllable molecularly imprinted electrochemical sensor (MIES) was fabricated through a one-step approach for detection of glutathione (GSH). The ternary Fe 3 O 4 @PANI/rGO nanocomposites were obtained by chemical oxidative polymerization and intercalation of Fe 3 O 4 @PANI into the graphene oxide layers via π–π stacking interaction, followed by reduction of graphene oxide in the presence of hydrazine hydrate . In molecular imprinting process, the pre-polymers, including GSH as template molecule, Fe 3 O 4 @PANI/rGO nanocomposites as functional monomers and pyrrole as both cross-linker and co-monomer, was assembled through N–H hydrogen bonds and the electrostatic interaction , and then was rapidly oriented onto the surface of MGCE under the magnetic field induction. Subsequently, the electrochemical GSH sensor was formed by electropolymerization. In this work, the ternary Fe 3 O 4 @PANI/rGO nanocomposites could not only provide available functionalized sites in the matrix to form hydrogen bond and electrostatic interaction with GSH, but also afford a promoting network for electron transfer . Moreover, the biomimetic sensing membrane could be controlled more conveniently and effectively by adjusting the magnetic field strength. The as-prepared controllable sensor showed good stability and reproducibility for the determination of GSH with the detection limit reaching 3 nmol L −1 (S/N = 3). In addition, the highly sensitive and selective biomimetic sensor has been successfully used for the clinical determination of GSH in biological samples.
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ACS Sustainable Chemistry & Engineering
·
2015
·
IF 4.642
Tao Ni,Liang Xu,Yupeng Sun,Wei Yao,Tingyang Dai,Yun Lu
We report a facile method to fabricate reduced graphene oxide/polypyrrole hydrogels (rGO/PPy) simply by combining the self-assembly process at room temperature with oxidation polymerization at elevated temperature. The as-prepared composite hydrogels possess a cross-linked 3D hierarchical porous structure and show a compression-tolerant property and a high specific capacitance of 473 F g–1 at 1 A g–1. In particular, 82% of the capacitance value has been maintained after charge–discharge for 5000 cycles, suggesting the great potential applications of the rGO/PPy hydrogels in high-quality energy storage devices. This study provides a novel reference way for the self-assembly of other conducting polymer and graphene sheets for different applications.
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