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1.
Kang Chen Yuanjin Xu Hong Zhang Lihua Nie Shouzhuo Yao 《Analytical and bioanalytical chemistry》1997,357(4):379-383
A novel surface acoustic wave-interdigitated array electrode (SAW-IDA) ammonia gas sensor is proposed. A gas-permeable membrane
is employed to separate the buffer solution in the inner cell of the gas-sensing probe from the sample solution in the detection
cell. The response of the IDA conductive electrodes is based on the impedance change of the buffer solution during ammonia
adsorption. Therefore, this gas sensor overcomes the influence of water vapour in the conventional film-coated SAW gas sensor
and can be used for the detection of gases in aqueous solutions. The ammonia sensor exhibits a favourable frequency response
to 5×10-7–1×10-3 mol/l ammonia. The optimal buffer composition and probe parameters have been determined. Dynamic range, response time, selectivity,
and temperature drift are discussed. The ammonia sensor was also applied to the determination of serum ammonia. Results were
in good agreement with those from the conventional enzymatic-spectrophotometric method.
Received: 1 December 1995/Revised: 9 April 1996/Accepted: 14 April 1996 相似文献
2.
A novel ion-selective sensor for procaine hydrochloride has been proposed and applied successfully to analysis of pharmaceutical
preparations. The sensor is based on modification of the Ag-electrode of an AT-cut piezoelectric quartz crystal with a PVC
membrane containing procaine tetraphenylborate. A linear relation between the logarithm of the response frequency and the
logarithm of the procaine hydrochloride concentration was found experimentally and could be explained by combination of a
modified Sauerbrey equation and the Freundlich isotherm. The detection range was from 8.3 × 10−8 to 5.0 × 10−3 M with a detection limit of 8.3 × 10−8 M. The selectivity of the sensor and the influence of experimental parameters such as solution pH and detection time were
investigated.
Received February 10, 1999. Revision October 10, 1999. 相似文献
3.
An optical sensor membrane is described for the determination of lanthanum(III) ions based on the immobilization of 4-hydroxysalophen
on a hydrolyzed triacetylcellulose membrane. 4-Hydroxysalophen is covalently bonded to a transparent hydrolyzed triacetylcellulose
film. The sensing membrane in contact with lanthanum ions at pH 4.0 changes color from white-yellow to orange (323 to 433
nm). Under the optimum conditions, the proposed membrane displayed a linear range from 1.0 × 10−6 to 1.0 × 10−2 M La(III) with a limit of detection of 1 × 10−7 M. The response time of the membrane was within 5–6 min depending on the concentration of La(III) ions. The selectivity of
the probe towards lanthanum ions was found to be excellent. The sensor was successfully applied to the determination of La(III)
in water, industrial waste water, and in NIST-615 (glass matrix) and NIST-3127a (lanthanum solution) samples with satisfactory
results. 相似文献
4.
A novel amperometric sensor for uric acid based on ordered mesoporous carbon modified pyrolytic graphite electrode was developed.
Uric acid oxidation was easily catalyzed by this electrode in a phosphate buffer solution at pH 7.0, with an anodic potential
decrease about 140 mV compared to bare pyrolytic graphite electrode. The uric acid level was determined by the amperometric
method, at a constant potential of 0.31 mV, the catalytic current of uric acid vs. its concentration showed a good linearity
in the range of 1.0 × 10−6−1.0 × 10−4 mol L−1, with a correlation coefficient of 0.999. The detection limit was 4.0 × 10−7 mol L−1. The proposed method could be effectively used for uric acid amperometric sensing in human urine. 相似文献
5.
A new simple and inexpensive optical chemical sensor for cadmium(II) ions is presented. The cadmium sensing system was prepared
by incorporating 2-amino-cyclopentene-1-dithiocarboxylic acid (ACDA) on a triacetylcellulose membrane. The absorption spectra of the optical sensor membrane in Cd(II) solution showed a maximum
peak at 430 nm. The proportionality in intensity of the membrane color on the optode to varying amounts of Cd(II) suggests
its potential applications for screening Cd(II) in aqueous samples by visual colorimetry. The sensor provided a wide concentration
range of 3.0 × 10−6–3.4 × 10−4 M of Cd(II) ions with a detection limit of 1.0 × 10−6 M (0.2 μg/mL). The relative standard deviations for eight replicate measurements of 8.0 × 10−6 and 5.0 × 10−5 M Cd(II) were 2.7 and 2.3%, respectively. The response time of the optode was 6 min. The influence of interfering ions on
the determination of 1.0 × 10−5 M Cd(II) was studied and the main interferences were removed by extraction method. The sensor was applied to the determination
of Cd(II) in water samples. 相似文献
6.
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
7.
Xiao-Gang Wang Ya-Juan Fan Zhi-Xian Hao Li-Hua Gan 《Russian Journal of Electrochemistry》2010,46(12):1402-1407
In pH 5.0, 0.1 mol l−1 NaAc-HAc buffer solution, 2,4-dinitrophenol and 2,5-dinitrophenol exhibited sensitive and distinguishable voltammetric responses
at the glassy carbon electrode modified with poly-aspartic acid. By measuring the reduction peak currents of nitro groups
in different positions, dinitrophenol isomers have been determined simultaneously and quantitatively. The linear calibration
ranges were 1.1 × 10−6–6.0 × 10−4 mol l−1 for 2,4-dinitrophenol and 7.0 × 10−7–6.0 × 10−4 mol l−1 for 2,5-dinitrophenol, with detection limits of 2.7 × 10−7 and 1.1 × 10−7 mol l-1 respectively. This method has been applied to the detection of dinitrophenols in simulation water sample, and the
recovery was from 96.7 to 102.5%. 相似文献
8.
H. Karimi-Maleh A. A. Ensafi A. R. Allafchian 《Journal of Solid State Electrochemistry》2010,14(1):9-15
A ferrocenedicarboxylic acid modified carbon paste electrode was constructed and used as a fast and sensitive tool for the
determination of captopril at trace level. It has been shown by direct current cyclic voltammetry and double step chronoamperometry
that ferrocenedicarboxylic acid can catalyze the oxidation of captopril in aqueous buffer solution and produces a sharp oxidation
peak current at about +0.49 vs. Ag/AgCl reference electrode. The square wave voltammetric peak currents of the electrode increased
linearly with the corresponding captopril concentration in the range of 3.0 × 10−7–1.4 × 10−4M with a detection limit of 9.1 × 10−8 M. The influence of pH and potential interfering substances on the determination of captopril were studied. Electrochemical
impedance spectroscopy was used to study the charge transfer properties at the electrode–solution interface. Finally, the
sensor was examined as a selective, simple, and precise new electrochemical sensor for the determination of captopril in real
samples, such as drug and urine, with satisfactory results. 相似文献
9.
This work reported for the first time the use of flow injection electrochemiluminescence (FI-ECL) sensor for the determination
of durabolin in an aqueous system based on CdTe quantum dot (QD) films. Aqueous CdTe colloidal solutions were prepared using
thioglycolic acid as a capping agent. Zetasizer Nano ZS (Malvern, UK) was employed to characterize the size of CdTe QDs. The
UV–vis and photoluminescence spectra of samples were systematically characterized. Indium tin oxide (ITO) slide glass was
modified with CdTe QDs by layer-by-layer self-assembly. CdTe QD films were packed into a homemade cell and used as a recognizer
of the FI-ECL sensor to determine durabolin. The intensive anodic ECL emission was obtained at a starting potential of +1.3 V
(vs. Ag/AgCl) in a carbonate bicarbonate buffer solution with a pH of 9.93 at an ITO electrode. The ECL intensity was correlated
linearly with the concentration of durabolin over the range of 1.0 × 10−8–1.0 × 10−5 g mL−1, and the detection limit was 2.5 × 10−9 g mL−1. The relative standard deviation for the determination of 1.0 × 10−6 g mL−1 durabolin was 1.04% (n = 11). This simple and sensitive sensor revealed good reproducibility for ECL analysis. As a result, the new FI-ECL sensor
had been successfully applied to the determination of durabolin in food samples. This strategy could be easily realized and
opened new avenues for the applications of QDs in ECL biosensing. 相似文献
10.
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
11.
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
12.
In pH 5.5, 0.1 mol l−1 HAc-NaAc buffer solution, trinitrophenol has been determined quantitatively with differential pulse voltammetry by detecting
its reduction peak currents at the glassy carbon electrode. The detection sensitivity was enhanced significantly by the addition
of the surfactant of cetyl pyridinium chloride, and the enhancement mechanism was also studied in detail. The linear calibration
range was 8.0 × 10−7 to 2.0 × 10−4 mol l−1, and the detection limit was established to be 1.9 × 10−7 mol l−1. This method has been applied to the determination of trinitrophenol in water sample, and the recovery was from 97.6 to 103.5%. 相似文献
13.
In this paper, the silver doped poly (L-glutamic acid) modified glassy carbon electrode (PLG-Ag/GCE) was fabricated through
an electrochemical immobilization. The modified electrode was used for simultaneous determination of uric acid (UA) and ascorbic acid (AA) in 0.1 M phosphate buffer solutions (PBS). The cyclic voltammetric signals of UA and AA were well separated with a potential
difference of 396 mV in pH 3.0 phosphate buffer solution. The linear calibration curves were obtained in the concentration
range 5.00 × 10−7–1.00 × 10−4 M for UA and 8.00 × 10-6–5.00 × 10−3 M for AA with the detection limits of 3 × 10−7 M and 4 × 10−6 M, respectively. The relative standard deviations were 1.3 and 1.0% for the determinations of UA and AA for 20 continuous
measurements. The signal was highly stable and reproducible. This method was successfully applied to the determination of
UA in human urine samples. 相似文献
14.
A poly(L-methionine) modified electrode, fabricated by electrochemical immobilization of the L-methionine on a glassy carbon
electrode, was used for simultaneous determination of dopamine and epinephrine through cyclic voltammetry. The electrochemical
properties of dopamine and epinephrine have been investigated. This sensor gave two separated cathodic peaks at −0.282 and
0.112 V for EP and DA, respectively. A linear response was obtained in the range of 5.0 × 10−7 to 1.0 × 10−4 mol l−1 for epinephrine, and 1.0 × 10−6 to 5.0 × 10−4 mol l−1 for dopamine. The detection limits were 3.6 × 10−7 mol l−1 and 4.2 × 10−7 mol l−1 for epinephrine and dopamine, respectively. This method was successfully applied for simultaneous determination of dopamine
and epinephrine in human urines.
The text was submitted by the authors in English. 相似文献
15.
Yufang Hu Zhaohui Zhang Huabin Zhang Lijuan Luo Shouzhuo Yao 《Journal of Solid State Electrochemistry》2012,16(3):857-867
A sensitive molecularly imprinted electrochemical sensor was developed for selective detection of streptomycin by combination
of mercaptoacetic acid-modified PbS nanoparticles with Au-coated Fe3O4 magnetic nanoparticles dispersed multi-walled carbon nanotubes doped chitosan film. The imprinted sensor was fabricated onto
the Au electrode via stepwise modification of nanocomposites and an electrodeposited thin film of molecularly imprinted polymers
via sol–gel technology. The morphologies and electrochemical behaviors of the imprinted sensor were characterized by scanning
electron microscope, cyclic voltammetry, and differential pulse voltammetry, respectively. The prepared sensor showed very
high recognition ability and selectivity for streptomycin. Under optimal conditions, the imprinted sensor displayed good electrocatalytic
activity to the redox of streptomycin. And the differential voltammetric anodic peak current was linear to the logarithm of
streptomycin concentration in the range from 1.0 × 10−6 to 1.0 × 10−3 mol L−1, and the detection limit obtained was 1.5 × 10−9 mol L−1. This proposed imprinted sensor was used successfully for streptomycin determination in different injection solution samples. 相似文献
16.
M. R. Ganjali P. Norouzi R. Dinarvand F. Faribod A. Moghimi 《Journal of Analytical Chemistry》2008,63(7):684-689
In this work, for the first time, we introduce a highly selective and sensitive Be(II) microsensor. 4-nitrobenzo-9-crown-3-ether
(NBCE) was used as a membrane-active component to prepare a Be(II)-selective polymeric membrane microelectrode. The electrode
exhibits a Nernstian response toward Be(II) ions over a very wide concentration range (1.0 × 10−4–1.0 × 10−10 M), with a detection limit of 3.5 × 10−11 M (∼350 pg/L). In fact, the electrode presents a fast response time in the whole concentration range (6 s). The proposed
microelectrode can be used for at least six weeks without any considerable divergence in the potentials. The proposed membrane
sensor revealed a selectivity toward Be(II) ions over a wide variety of other metal ions including common alkali, alkaline-earth,
and rare-earth ions. It could be used in the pH range of 3.0–11.5. The microelectrode was successfully used as an indicator
electrode for the titration of 20 mL of 1.0 × 10−6 M Be2+ solution with 1.0 × 10−4 M of EDTA. It was also applied to the direct determination of beryllium ions in beryl and binary mixtures.
The text was submitted by the authors in English. 相似文献
17.
Fei Wang Changzheng Xin Yanju Wu Yumei Gao Baoxian Ye 《Journal of Analytical Chemistry》2011,66(1):60-65
A glassy carbon electrode coated with film of 4-tert-butyl-1-(ethoxycarbonylmethoxy)thiacalix[4]arene is designed for the
determination of trace amounts of Ag+. Compared with bare glassy carbon electrode, the modified electrode can greatly improve the measuring sensitivity for Ag+. Under the optimum experimental conditions, the modified electrode in B-R buffer solution (pH 4.5) shows a linear voltammetric
response in the range of 5.0 × 10−8–3.0 × 10−6 M with detection limit 1.0 × 10−8 M for Ag+. The high sensitivity, selectivity, and stability of modified electrode also demonstrate its practical application for a
simple, rapid and economical determination of Ag+ in water samples. 相似文献
18.
Hassan Ali Zamani Mohammad Reza Ganjali Masoud Salavati-Niasari 《Transition Metal Chemistry》2008,33(8):995-1001
A Fe3+ ion-selective membrane sensor was fabricated from polyvinyl chloride (PVC) matrix membrane containing bis-bidentate Schiff
base (BBS) as a neutral carrier, sodium tetraphenyl borate (NaTPB) as anionic excluder, and o-nitrophenyloctyl ether (NPOE) as a plasticizing solvent mediator. The effects of the membrane composition, pH, and additive
anionic influence on the response properties were investigated. The best performance was obtained with a membrane containing
32% PVC, 62.5% NPOE, 3% BBS, and 2.5% NaTPB. The electrode shows a Nernstian behavior (slope of 19.3 ± 0.6) over a very wide
iron ion concentration range (1.0 × 10−7–1.0 × 10−2 M) and has a low detection limit (7.4 × 10−8 M). The potentiometric response of the sensor is independent of pH of the solution in the pH range 1.9–5.1. The proposed
sensor has a very low response time (<15 s) and a good selectivity relative to a wide variety of other metal ions including
common alkali, alkaline earth, heavy, and transition metal ions. The electrode can be used for at least 60 days without any
considerable divergence in potentials. The proposed sensor was successfully applied as an indicator electrode for the potentiometric
titration of 1.0 × 10−2 M Fe3+ ions with a 1.0 × 10−4 M EDTA and the direct determination of Fe3+ in mineral water and wastewater samples. 相似文献
19.
M. H. Pournaghi-Azar F. Ahour M. S. Hejazi 《Analytical and bioanalytical chemistry》2010,397(8):3581-3587
Development of an electrochemical DNA biosensor for the direct detection and discrimination of double-stranded oligonucleotide
(dsDNA) corresponding to hepatitis C virus genotype 3a, without its denaturation, using a gold electrode is described. The
electrochemical DNA sensor relies on the modification of the gold electrode with 6-mercapto-1-hexanol and a self-assembled
monolayer of 14-mer peptide nucleic acid probe, related to the hepatitis C virus genotype 3a core/E1 region. The increase
of differential pulse voltammetric responses of methylene blue, upon hybridization of the self-assembled probe with the target
ds-DNA to form a triplex is the principle behind the detection and discrimination. Some hybridization experiments with non-complementary
oligonucleotides were carried out to assess whether the developed DNA sensor responds selectively to the ds-DNA target. Diagnostic
performance of the biosensor is described and the detection limit was found to be 1.8 × 10−12 M in phosphate buffer solution, pH 7.0. The relative standard deviation of measurements of 100 pM of target ds-DNA performed
with three independent probe-modified electrodes was 3.1%, indicating a remarkable reproducibility of the detection method. 相似文献
20.
Pyrene-tetramethylpiperidinyl (Pyr-Tempo) as a spin label fluorescent probe for iron(II) was synthesized. It exhibited weak
fluorescence (λexc/λem = 346/399 nm) in aqueous solution due to an intramolecular quenching pathway. A method for determination of iron(II) was
proposed based on the fluorescence enhancement of the probe in the presence of iron(II) in acidic medium. Under optimum conditions,
the fluorescence enhancement of Pyr-Tempo is linearly proportional to the iron(II) concentration range of 6.0 × 10−8 to 9.6 × 10−6 mol L−1 with a detection limit of 8.0 × 10−9 mol L−1. The relative standard deviation (RSD) of six replicate measurements is 1.95% for 3.0 × 10−7 mol L−1 iron(II). The developed spin label fluorescence probe is found to be rapidly and sensitively responsive to iron(II) with
high selectivity compared to existing fluorescence methods. The proposed method was successfully applied to iron(II) detection
in five real samples with satisfactory results obtained by manual UV/Vis spectrophotometry (standard method) with 1,10-phenanthroline. 相似文献