In this work, a glassy carbon electrode (GCE) modified with poly (diphenylamine)/multi-walled carbon nanotubes-β-cyclodextrin (PDPA/MWCNT-β-CD) film was constructed and used for the determination of 4-nitrophenol (4-NP). Diphenylamine was successfully electropolymerised onto MWCNT-β-CD-modified GCE by cyclic voltammetry in monomer solution and 5 mol L?1 H2SO4. The surface morphology of PDPA/MWCNT-β-CD film was characterised using scanning electron microscopy and electrochemical impedance spectroscopy. After adsorption of 4-NP on PDPA/MWCNT-β-CD at 0.2 V for 150 s, it showed a well-defined reduction peak in phosphate buffer solution at pH = 7. The PDPA/MWCNT-β-CD film enhanced the reduction peak current due to the complex formation between β-CD and 4-NP, presence of conductive polymer film as electron transfer mediator and also ability of MWCNTs for strong adsorptive and catalytic effect. Peak current increased linearly with 4-NP concentration in the range of 0.1 to 13.9 µg L?1. The detection limit was obtained as 0.02 µg L?1, which is better than other reported detection limits for the determination of 4-NP. The results showed that modified electrode has good sensitivity and selectivity. This sensor was used for the determination of 4-NP in water samples. 相似文献
To improve the performance of dopamine (DA) detection in the presence of ascorbic acid (AA) and uric acid (UA), sodium diphenylamine sulfonate/polypyrrole/multi‐walled carbon nanotubes (SDPAS/PPy/CNTs) film was fabricated on the surface of gold electrode through one‐pot polymerization initiated by electrochemical oxidation. SDPAS were covalently embedded into the backbone of PPy to endow the resultant film with numerous negative‐charged terminals, resulting in selective pre‐adsorption of protonated DA+ on the electrode and switching the following anodic reaction to be an adsorption‐controlled process. The detection of DA in the presence of AA and UA by square wave voltammetry method showed an outstanding repeatability with the relative standard deviation of 0.45 %. A good linear relationship was observed between the oxidative peak current and the concentration of DA in the range of 0.827–104 μM (R2=0.993), and the limit of detection (LOD) was calculated to be 0.105 μM (S/N=3). 相似文献
Based on the location of bromine substituents and conjugation matrix, a new substituent po-sition index 0X not only was defined, but also molecular shape indexes Km and electronega-tivity distance vectors Mm of diphenylamine and 209 kinds of polybrominated diphenylamine (PBDPA) molecules were calculated. Then the quantitative structure-property relationships (QSPR) among the thermodynamic properties of 210 organic pollutants and 0X、K3、M29、M36 were founded by Leaps-and-Bounds regression. Using the four structural parameters as input neurons of the artificial neural network, three satisfactory QSPR models with network structures of 4:21:1, 4:24:1, and 4:24:1 respectively, were achieved by the back-propagation algorithm. The total correlation coefficients R were 0.9999, 0.9997, and 0.9995 respectively and the standard errors S were 1.036, 1.469, and 1.510 respectively. The relative mean deviation between the predicted value and the experimental value of S?,ΔfH? and ΔfG? were 0.11%, 0.34% and 0.24% respectively, which indicated that the QSPR models had good stability and superior predictive ability. The results showed that there were good nonlinear correlations between the thermodynamic properties of PBDPAs and the four structural pa-rameters. Thus, it was concluded that the ANN models established by the new substituent position index were fully applicable to predict properties of PBDPAs. 相似文献
In this work a kinetic spectrophotometric method for the determination of trace amounts of vanadium is presented. The method
is based on the catalytic effect of the vanadium(V) on the reaction between diphenylamine (DPhA) and hydrogen peroxide in
a concentrated solution of formic acid. The formation of the deep-blue oxidation product is followed by a filter spectrophotometer,
equipped with an optical fiber assembly, on line with a PC provided with the suitable software. The measurements were taken
at 583 nm, with an immersed type cell of 1 cm light path length. The optimization of the operating conditions regarding concentrations
of the reagents, temperature and interferences are also investigated. The working curve is linear over the concentration range
0.40–4.0 μg/ml vanadium(V). The relative standard deviation for a standard solution of 0.6 μg/ml of vanadium is 0.5% (n = 5).
The proposed method proved highly sensitive, selective and relatively rapid for the assay of vanadium, at low level of 0.40 μg/ml
without any pre-concentration step. The method was applied to alloys and cosmetics samples. The results were compared to those
received with a reference method. Good agreement was attained, with a mean error of 0.5%.
Received February 25, 2000. Revision May 15, 2000. 相似文献
Summary: Poly(arylene ether amine)s were synthesized by a nucleophilic aromatic substitution polycondensation of bis[4‐fluoro‐3‐(trifluoromethyl)phenyl]amine with several bisphenols. Even though the monomer has an electron‐donating diphenylamine moiety, which normally deactivates a nucleophilic aromatic substitution (SNAr) reaction, the polymerization proceeded by a SNAr reaction to give high‐molecular‐weight polymers. The polymers show good solubility in common organic solvents and have Tgs in the range of 123 °C to 177 °C.
High‐molecular‐weight poly(arylene ether amine)s synthesized by a SNAr reaction with the monomer containing an electron‐donating diphenylamine moiety. 相似文献
The synthesis of N-(2,3-epoxypropyl)diphenylamine is reported. It was found that thermal opening of the oxirane ring of N-(2,3-epoxypropyl)diphenylamine
occurred both at the secondary and the tertiary carbon atoms but the basic reaction product is 3-hydroxy-1-phenyl-1,2,3,4-tetrahydroquinoline.
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Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 852–855, June, 2007. 相似文献
Solutions of benzidine and diphenylamine in benzene produce cation radical on the surface of zeolite, γ-alumina, MoO3 and MoO3 doped γ-alumina and zeolite. MoO3 doped zeolite behaved much differently than V2O5 doped zeolite in presence of benzidine or diphenylamine in benzene. 相似文献