共查询到20条相似文献,搜索用时 31 毫秒
1.
Lin Cui Lifang Li Shiyun Ai Huanshun Yin Peng Ju Tao Liu 《Journal of Solid State Electrochemistry》2011,15(6):1253-1261
Guanosine-5′-monophosphate (GMP) was investigated the electrochemical behaviors based on solid-phase extractionon (SPE) at
Cu-Mg-Al hydrotalcite-like compound (HTLC) modified glass carbon electrode. Cu-Mg-Al hydrotalcite-like compound (HTLC) was
proved as a new sorbent for SPE of GMP, which showed an irreversible adsorption oxidation process on the HTLC/GCE with the
oxidation peak potential located at 1.15 V (vs. SCE) in a pH 5.0 acetate buffer solution. Influencing factors of the electrochemical
behavior of GMP on the HLTC/GCE were optimized and kinetic parameters were calculated. Under the optimal conditions, with
differential pulse voltammetry (DPV), a linear relationship was obtained between the oxidation peak current and the GMP concentration
in the range from 1.0 × 10− 6 to 8.0 × 10−4 mol L−1 with the detection limit as 5.0 × 10−7 mol L−1 (signal-to-noise ratio of 3). The modified electrode surface has very good reproducibility and stability. 相似文献
2.
Chunya Li 《Mikrochimica acta》2007,157(1-2):21-26
Multi-wall carbon nanotubes (MWNT) were dispersed into water in the presence of dicetyl phosphate (DCP), and MWNT-DCP composite
film coated glassy carbon electrodes (GCE) were constructed. The electrochemical properties of 2-chlorophenol at a bare GCE
and MWNT-DCP modified GCE were compared. It was found that MWNT-DCP modified GCEs significantly enhance the oxidation peak
current of 2-chlorophenol and lowers its oxidation overpotential, suggesting great potential in the sensitive determination
of 2-chlorophenol. Finally, a sensitive and simple voltammetric method was developed for the determination of 2-chlorophenol.
The oxidation peak current increases linearly with the concentration in the range of 1.0 × 10−7–2.0 × 10−5 mol L−1, and the detection limit is 4.0 × 10−8 mol L−1 for 2 min accumulation. The method was successfully used to determine 2-chlorophenol in waste water samples. 相似文献
3.
Single-wall carbon nanotubes (SWNT) were dispersed into water in the presence of dicetyl phosphate (DCP), and then a SWNT-DCP
film-coated glassy carbon electrode (GCE) was constructed. The electrochemical behavior of acetaminophen at bare GCE and SWNT-DCP
modified GCE were compared, suggesting that the SWNT-DCP-modified GCE significantly enhances the oxidation peak current of
acetaminophen. A sensitive and simple electrochemical method with a good linear relationship in the range of 1.0 × 10−7–2.0 × 10−5 mol L−1, was developed for the determination of acetaminophen. The detection limit is 4.0 × 10−8 mol L−1 for 3-min accumulation. This method was successfully demonstrated with tablets. 相似文献
4.
Xiaoying Liu Yonghong Li Xinsheng Liu Xiandong Zeng Bo Kong Shenglian Luo Wanzhi Wei 《Journal of Solid State Electrochemistry》2012,16(3):883-889
A simple sensor based on bare carbon ionic liquid electrode was fabricated for simultaneous determination of dihydroxybenzene
isomers in 0.1 mol L−1 phosphate buffer solution (pH 6.0). The oxidation peak potential of hydroquinone was about 0.136 V, catechol was about 0.240 V,
and resorcinol 0.632 V by differential pulse voltammetric measurements, which indicated that the dihydroxybenzene isomers
could be separated absolutely. The sensor showed wide linear behaviors in the range of 5.0 × 10−7–2.0 × 10−4 mol L−1 for hydroquinone and catechol, 3.5 × 10−6–1.535 × 10−4 mol L−1 for resorcinol, respectively. And the detection limits of the three dihydroxybenzene isomers were 5.0 × 10−8, 2.0 × 10−7, 5.0 × 10−7 mol L−1, respectively (S/N = 3). The proposed method could be applied to the determination of dihydroxybenzene isomers in artificial wastewater and
the recovery was from 93.9% to 104.6%. 相似文献
5.
We report a sensitive and convenient voltammetric method for the direct determination of 10-hydroxycamptothecin (HCPT). At
a multi-wall carbon nanotube (MWNT)-modified electrode, HCPT yields a very sensitive and well-shaped oxidation peak, which
can be used as analytical signal for HCPT determination. Compared with the poor electrochemical signal at the unmodified GCE,
the electrochemical response of HCPT at the MWNT-modified GCE was greatly improved, as confirmed by the significant peak current
enhancement. This result indicates that the MWNT-modified GCE has great potential in the sensitive determination of HCPT.
Based on this, a very sensitive and simple electrochemical method was proposed for HCPT determination after all the experimental
parameters were optimized. The newly-proposed method possesses very low detection limit (2 × 10−9 mol L−1) and wider linear range (from 1 × 10−8 to 4 × 10−6 mol L−1). Rapid and simple sample analysis is another advantage. Finally, this method was successfully demonstrated using HCPT drugs. 相似文献
6.
A voltammetric sensor for the determination of parathion has been developed based on the use of a poly(carmine) film electrode.
The reduction of parathion at the poly(carmine) modified glassy carbon electrode (GCE) is studied by cyclic voltammetry (CV)
and linear scan voltammetry (LSV). Parathion yields a well-defined reduction peak at a potential of −0.595 V on the poly(carmine)
modified GCE in pH 6.0 phosphate buffer solution (PBS). Compared with that on a bare GCE, the reduction peak current of parathion
is significantly enhanced. All the experimental parameters are optimized for the determination of parathion. The reduction
peak current is linear with the parathion concentration in the range of 5.0 × 10−8 to 1.0 × 10−5 mol L−1, and the detection limit is 1.0 × 10−8 mol L−1. 相似文献
7.
Ying Xu Fei Wang Le Wang Fangyuan Zhao Baocheng Yang Baoxian Ye 《Journal of Solid State Electrochemistry》2012,16(4):1473-1480
A novel voltammetric sensor, based on single-walled carbon nanotubes (SWNT) dispersed in Nafion and modified glassy carbon
electrode (GCE), was fabricated and used to determine the trace amounts of dihydromyricetin (DMY). The electrochemical behavior
of DMY at this sensor was investigated in 0.1 mol L−1 sulfuric acid solutions + 0.1 mol L−1 NaCl by cyclic voltammetry and squarewave voltammetry. Compared with bare GCE, the electrode presented an excellent response
of DMY through an adsorption-controlled quasi-reversible process. Under the optimum conditions, the response peak currents
were linear relationship with the DMY concentrations in the range of 1.0 × 10−7–1.0 × 10−5 mol L−1 with a detection limit of 9 × 10−8 mol L−1. Based on this voltammetric sensor, a simple and sensitive electroanalytical method for DMY was proposed and applied to quantitative
determination of DMY in Ampelopsis grossedentata samples. In addition, the oxidation mechanism was proposed and discussed, which could be a reference for the pharmacological
action of DMY in clinical study. 相似文献
8.
A novel L-cysteine film modified electrode has been fabricated by means of an electrochemical oxidation procedure, and it
was successfully applied to the electrochemical determination of acetaminophen. This method utilizes the electrooxidation
of amines to their analogous cation radicals to form a chemically stable covalent linkage between the nitrogen atom of the
amine and edge plane sites at the glassy carbon electrode surface. The electrochemical behaviour of acetaminophen at the film
electrode was investigated in 0.1 mol L−1 phosphate buffer (pH 6.20). It was found that the redox peak current of acetaminophen was enhanced greatly on the film electrode.
Linearity between the oxidation peak current and the acetaminophen concentration was obtained in the range of 1.0 × 10−4–2.0 × 10−7 mol L−1 with a detection limit of 5.0 × 10−8 mol L−1. For seven parallel detections of 1.0 × 10−5 mol L−1 acetaminophen, the relative standard deviation (RSD) was 1.46%, suggesting that the film electrode has excellent reproducibility.
Application to the determination of acetaminophen in drug tablets and human urine demonstrated that the film electrode has
good stability and high sensitivity. 相似文献
9.
Covalent modification of a glassy carbon electrode with penicillamine for simultaneous determination of hydroquinone and catechol 总被引:1,自引:0,他引:1
Liang Wang Peng Fei Huang Jun Yue Bai Hong Jing Wang Li Ying Zhang Yu Qing Zhao 《Mikrochimica acta》2007,158(1-2):151-157
A simple and highly selective electrochemical method has been developed for the simultaneous determination of hydroquinone
(HQ) and catechol (CC) at a glassy carbon electrode covalently modified with penicillamine (Pen). The electrode is used for
the simultaneous electrochemical determination of HQ and CC and shows an excellent electrocatalytical effect on the oxidation
of HQ and CC upon cyclic voltammetry in acetate buffer solution of pH 5.0. In differential pulse voltammetric measurements,
the modified electrode was able to separate the oxidation peak potentials of HQ and CC present in binary mixtures by about
103 mV although the bare electrode gave a single broad response. The determination limit of HQ in the presence of 0.1 mmol L−1 CC was 1.0 × 10−6 mol L−1, and the determination limit of CC in the presence of 0.1 mmol L−1 HQ was 6.0 × 10−7 mol L−1. The method was applied to the simultaneous determination of HQ and CC in a water sample. It is simple and highly selective. 相似文献
10.
Gongjun Yang Xilong Qu Ming Shen Chengyin Wang Qishu Qu Xiaoya Hu 《Mikrochimica acta》2008,160(1-2):275-281
Poly(phenol red) (denoted as PPR) films were electrochemically synthesized on the surface of a glassy carbon electrode (GCE)
by cyclic voltammetry to obtain a chemically modified electrode (denoted as PPR-GCE). The growth mechanism of PPR films was
studied by attenuated total reflection spectroscopy. This PPR-GCE was used to develop a novel and reliable method for the
determination of trace Pb2+ by anodic stripping differential pulse voltammetry. At optimum conditions, the anodic peak exhibits a good linear concentration
dependence in the range from 5.0 × 10−9 to 5.0 × 10−7 mol L−1 (r = 0.9989). The detection limit is 2.0 × 10−9 mol L−1 (S/N = 3). The method was employed to determine trace levels of Pb2+ in industrial waste water samples.
Correspondence: Gongjun Yang, Ming Shen, College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002,
P.R. China 相似文献
11.
Sensitive fluorescent probes for determination of hydrogen peroxide and glucose based on enzyme-immobilized magnetite/silica nanoparticles 总被引:2,自引:0,他引:2
Qing Chang Lihua Zhu Guodong Jiang Heqing Tang 《Analytical and bioanalytical chemistry》2009,395(7):2377-2385
Sensitive fluorescent probes for the determination of hydrogen peroxide and glucose were developed by immobilizing enzyme
horseradish peroxidase (HRP) on Fe3O4/SiO2 magnetic core–shell nanoparticles in the presence of glutaraldehyde. Besides its excellent catalytic activity, the immobilized
enzyme could be easily and completely recovered by a magnetic separation, and the recovered HRP-immobilized Fe3O4/SiO2 nanoparticles were able to be used repeatedly as catalysts without deactivation. The HRP-immobilized nanoparticles were able
to activate hydrogen peroxide (H2O2), which oxidized non-fluorescent 3-(4-hydroxyphenyl)propionic acid to a fluorescent product with an emission maximum at 409 nm.
Under optimized conditions, a linear calibration curve was obtained over the H2O2 concentrations ranging from 5.0 × 10−9 to 1.0 × 10−5 mol L−1, with a detection limit of 2.1 × 10−9 mol L−1. By simultaneously using glucose oxidase and HRP-immobilized Fe3O4/SiO2 nanoparticles, a sensitive and selective analytical method for the glucose detection was established. The fluorescence intensity
of the product responded well linearly to glucose concentration in the range from 5.0 × 10−8 to 5.0 × 10−5 mol L−1 with a detection limit of 1.8 × 10−8 mol L−1. The proposed method was successfully applied for the determination of glucose in human serum sample. 相似文献
12.
A 3-amino-5-mercapto-1,2,4-triazole (TA) self-assembled monolayer-modified gold electrode (TA SAM/Au) is characterized by
X-ray photoelectron spectroscopy, A.C. impedance, cyclic voltammetry, chronoamperometry and chronocoulometry. The TA SAM/Au
exhibited good promotion of the electrochemical oxidation of dopamine. Some electrochemical parameters of dopamine such as
electron transfer number, exchange current density, standard heterogeneous rate constant, diffusion coefficient, etc., were
measured by different electrochemical methods. The peak currents of dopamine were linearly dependent on its concentration
in the range of 1.5 × 10−6–1.0 × 10−4 mol L−1, with a detection limit of 5.0 × 10−7 mol L−1. The oxidative peak potentials of dopamine and ascorbic acid were well separated at about 190 ± 10 mV in pH 2.0 BR buffers
at TA SAM/Au, the oxidation peak current increases approximately linearly with increasing concentration of both dopamine and
ascorbic acid in the concentration range of 9.98 × 10−6–4.54 × 10−4 mol L−1. It can be used for simultaneous determination of dopamine and ascorbic acid. 相似文献
13.
The electrooxidative behaviour and determination of quetiapine (QTP), a dibenzothiazepine derivative and antipsychotic agent,
on a glassy carbon disc electrode was investigated using cyclic (CV), linear sweep (LSV), differential pulse (DPV) and Osteryoung
square wave voltammetry (OSWV). Fully validated DP and SW voltammetric procedures are described for the determination of QTP.
QTP in pH 3.5 acetate buffer solution presents a well-defined anodic response, studied by the proposed methods. This main
response was due to the irreversible, diffusion-controlled, one-electron and one-proton oxidation of the aliphatic nitrogen
of the piperazine ring. Under optimal conditions, a detection limit of 4.0 × 10−8 mol L−1 for DPV and 1.33 × 10−7 mol L−1 for OSWV, and a linear calibration graph in the range from 4.0 × 10−6 to 2.0 × 10−4 mol L−1 were obtained for both methods. The procedure was successfully applied to the determination of the drug in tablets, human
serum and human urine with good recoveries. The detection limits were 6.20 × 10−7 mol L−1 and 5.92 × 10−7 mol L−1 in human serum and 1.44 × 10−7 mol L−1 and 1.31 × 10−6 mol L−1 in human urine, for the DPV and OSWV method, respectively. 相似文献
14.
A rapid, highly sensitive and selective fluorogenic method for the determination of traces of nitrite is described. It is
based on the reaction of weakly fluorescent 1,3,5,7-tetramethyl-8-(3,4-diaminophenyl)-difluoroboradiaza-s-indacence (DAMBO) and nitrite in acidic aqueous solution to give 1,3,5,7-tetramethyl-8-(5-benzotriazolyl)-difluoroboradiaza-s-indacene (DAMBO-T), which is highly fluorescent. The optimum reaction conditions and other analytical parameters are investigated
to enhance the sensitivity of the method. The fluorescence enhancement at 507 nm is linearly related to the concentration
of nitrite in the range of 6.0 × 10−9–5.0 × 10−7 mol L−1 with a correlation coefficient of R = 0.9995 (n = 10) and a detection limit of 1.0 × 10−10 mol L−1. The R.S.D. is 1.12% (n = 10). The method is applied to the determination of nitrite in human saliva samples with the recoveries of 96. 24–105.30%.
Correspondence: Ke-Jing Huang, Department of Chemistry, Wuhan University, Wuhan 430072, P.R. China 相似文献
15.
Jun Yue Bai Liang Wang Hong Jing Wang Peng Fei Huang Yu Qing Zhao Sheng Di Fan 《Mikrochimica acta》2006,156(3-4):321-326
The electrochemical behavior of epinephrine (EP) at a mercaptoacetic acid (MAA) self-assembled monolayer modified gold electrode
was studied. The MAA/Au electrode is demonstrated to promote the electrochemical response of epinephrine by cyclic voltammetry.
The possible reaction mechanism is also discussed. The diffusion coefficient D of EP is 6.85 × 10−6 cm2 s−1. In 0.1 mol L−1 phosphate buffer (pH 7.20), a sensitive oxidation peak was observed at 0.177 V, and the peak current is proportional to the
concentration of EP in the range of 1.0 × 10−5–2.0 × 10−4 mol L−1 and 1.0 × 10−7–1.0 × 10−6 mol L−1. The detection limit is 5 × 10−8 mol L−1. The modified electrode is highly stable and can be applied to the determination of EP in practical injection samples. The
method is simple, quick, sensitive and accurate. 相似文献
16.
Gang Li Suling Yang Lingbo Qu Ran Yang Jianjun Li 《Journal of Solid State Electrochemistry》2011,15(1):161-166
A Nafion/multi-wall carbon nanotubes (MWNT) composite film-modified electrode was fabricated. The modified electrode showed
excellent electrocatalytic activity toward ascorbic acid (AA) and uric acid (UA) in 0.1-mol L−1 NaCl medium (pH 6.5). Compared to the bare electrode that only displayed a broad and overlapped oxidation peak, the Nafion/MWNT
film-modified electrode not only remarkably enhanced the anodic peak currents of AA and UA but also avoided the overlapping
of the anodic peaks of AA and UA with a 320-mV separation of both peaks. Under the optimized conditions, the peak currents
of AA and UA were proportional to their concentration at the ranges of 8.0 × 10−5 to 6.0 × 10−3 mol L−1 and 6.0 × 10−7 to 8.0 × 10−5 mol L−1, respectively. The proposed method was used for the detection of AA and UA in real samples with satisfactory results. 相似文献
17.
The voltammetric determination of 2-mercaptobenzimidazole (MBI) was studied by using a glassy carbon electrode (GCE) coated
with polymeric nickel and copper tetraaminophthalocyanine (poly-NiTAPc and poly-CuTAPc) membrane. The polymeric membrane decreases
the overpotential of oxidation of MBI by 136.2 and 115.0 mV and increases the oxidation peak current by about 3.4 and 3.3
times, while the reduction peak potential shifts positively by 113.0 and 84.1 mV and the peak current increases by about 10
and 7 times in 0.1 mol·l−1 phosphate buffer solution (PBS) at pH = 2.0 for poly-NiTAPc and poly-CuTAPc, respectively, compared to the unmodified GCE.
The results indicated that the developed electrode exhibited efficient electrocatalytic activity for MBI with relatively high
sensitivity, stability, and long life. The oxidation and reduction peak currents of MBI were linear to its concentrations
ranging from 8.0 × 10−5 to 1.0 × 10−3 mol·l−1 at poly-NiTAPc and from 2.0 × 10−5 to 1.0 × 10−3 mol·l−1 at poly-NiTAPc membranes modified electrodes, respectively, with a low limit of detection. 相似文献
18.
A compact miniaturized continuous flow system for the determination of urea content in milk 总被引:1,自引:0,他引:1
Willian Toito Suarez Osmundo Dantas Pessoa-Neto Vagner Bezerra dos Santos Ana Rita de Araujo Nogueira Ronaldo Censi Faria Orlando Fatibello-Filho Mar Puyol Julián Alonso 《Analytical and bioanalytical chemistry》2010,398(3):1525-1533
A multicommutation-based flow system with photometric detection was developed, employing an analytical microsystem constructed
with low temperature co-fired ceramics (LTCC) technology, a solid-phase reactor containing particles of Canavalia ensiformis DC (urease source) immobilized with glutaraldehyde, and a mini-photometer coupled directly to the microsystem which monolithically
integrates a continuous flow cell. The determination of urea in milk was based on the hydrolysis of urea in the solid-phase
reactor and the ammonium ions produced were monitored using the Berthelot reaction. The analytical curve was linear in the
urea concentration range from 1.0 × 10−4 to 5.0 × 10−3 mol L−1 with a limit of detection of 8.0 × 10−6 mol L−1. The relative standard deviation (RSD) for a 2.0 × 10−3 mol L−1 urea solution was lower than 0.4% (n = 10) and the sample throughput was 13 h−1. To check the reproducibility of the flow system, calibration curves were obtained with freshly prepared solutions on different
days and the RSD obtained was 4.7% (n = 6). Accuracy was assessed by comparing the results of the proposed method with those from the official procedure and the
data are in close agreement, at a 95% confidence level. 相似文献
19.
A sensitive adsorptive anodic stripping procedure for the determination of trace zirconium at a carbon paste electrode (CPE)
has been developed. The method is based on adsorptive accumulation of the Zr(IV)-alizarin red S(ARS) complex onto the surface
of the CPE, followed by oxidation of adsorbed species. The optimal experimental conditions include the use of 0.10 mol · L−1 ammonium acetate buffer (pH 4.3), ARS, an accumulation potential of 0.20 V (versus SCE), an accumulation time of 2 min, a
scan rate of 200 mV · s−1 and a second-order derivative linear scan mode. The oxidation peak for the complex appears at 0.69 V. The peak current is
proportional to the concentration of Zr(IV) over the range of 1.0 × 10−9–2.0 × 10−7 mol · L−1, and the detection limit is 3 × 10−10 mol · L−1 for a 2 min adsorption time. The relative standard deviations (n = 8) for 5.0 × 10−8 and 5.0 × 10−9 mol · L−1 Zr(IV) are 3.3 and 4.8%, respectively. The proposed method was applied to the determination of zirconium in ore samples with
satisfactory results. 相似文献
20.
A method for the determination of trace clenbuterol is described. Multi-walled carbon nanotubes (MWCNTs)-Nafion composite
was used to modify the glassy carbon electrode (GCE). The modified electrode showed high sensitivity and good selectivity
for clenbuterol detection. It offered a linear range of 1.0 × 10−9–1.0 × 10−6 mol · L−1 with a detection limit of 5.0 × 10−10 mol · L−1 in pH = 1.2 solution. The oxidation mechanism of clenbuterol on the electrode was also investigated.
Correspondence: Xiao-Ya Hu, Department of Chemistry, Yang Zhou University, Yang Zhou, Jiang Su, P.R. China 相似文献