共查询到20条相似文献,搜索用时 15 毫秒
1.
Won-Sik Han Jang-Ki Kim Koo-Chun Chung Joo-Yeon Hong Jong-Ki Hong Jeong-Hoon Kim Tae-Kee Hong 《Journal of Analytical Chemistry》2010,65(10):1035-1040
Udenafil is an oral agent for treating male erectile dysfunction. The poly(aniline) solid contact selective electrodes for
udenafil have been fabricated from PVC cocktail solutions with three ion selective ion pairs. This solid contact electrode
contains three layers of Pt/electro-conductive poly(aniline) polymer/PVC film with an ionophore with a thickness of 2.5 ±
0.1 mm. We compared the slopes of EMF responses and the response range of a solid contact electrode based on Udenafil-TmCIPB
ion pair with those based on Udenafil-PMA and Udenafil-TPB ion pairs and showed that the response slopes were influenced by
plasticizers. The EMF response slopes of Udenafil-TmCIPB-based solid contact electrodes equalled 58.0 mV/decade (at 20 ± 0.2°C)
and their linear response dynamic ranges were 1.0 × 10−2∼1.0 × 10−5.85 M (r
2 = 0.9984). When electrodes with 6 different plasticizers based on Udenafil-TmCIPB were compared, as the dielectric constant
of PVC plasticizer increased, so was the response slope at the same time. Having applied the electrodes to artificial serum
directly, we could get same satisfactory results [Nernstian slope: 60.3 mV/decade, dynamic range: 1.0 × 10−2∼1.0 × 10−5.78 M (r
2 = 0.9978) in artificial serum]. Solid contact electrodes with Udenafil-TmCIPB have shown the best selectivity, reproducibility
of EMF, long-term stability, and short response time (< 20 s). 相似文献
2.
A triiodide-selective electrode based on copper (II)-Schiff base complex as a membrane carrier is proposed. The electrode
was prepared by incorporating the carrier into a plasticized polyvinylchloride (PVC) membrane and was directly coated on the
surface of a graphite electrode. The obtained electrode showed a near Nernstian slope of 57.0 ± 0.4 mV/decade to I
3
−
ions over an activity range of 1.0 × 10−5−1.0 × 10−1 M with a limit of detection of 4.8 × 10−6 M. The response time of the electrode was fast (5 s) and the electrode could be used for about 2 months without considerable
divergence in response. The potentiometric selectivity coefficients were evaluated and displayed anti-Hofmeister behavior.
The electrode was used as an indicator electrode in the potentiometric titration of the triiodide ion and in the determination
of ascorbic acid in vitamin C tablets.
The text was submitted by the authors in English. 相似文献
3.
Mojtaba Shamsipur Sohrab Ershad Naser Samadi Abloghasem Moghimi Hossein Aghabozorg 《Journal of Solid State Electrochemistry》2005,9(11):788-793
A new modified carbon paste electrode based on a recently synthesized mercury (II) complex of a pyridine containing proton
transfer compound as a suitable carrier for Br− ion is described. The electrode has a linear dynamic range between 3.00×10−2 and 1.0×10−5 M with a near-Nernastian slope of 61.0±0.9 mV per decade and a detection limit of 4.0×10−6 M (0.32 ppm). The potentiometric response is independent of the pH of the solution in the pH range 4.0–8.3. The electrode
possesses the advantages of low resistance, fast response and good over a variety of other anions. It was applied as an indicator
electrode in potentiometric titration of bromide ions and for the recovery of Br− from tap water. 相似文献
4.
Reza Ansari Ali Fallah Delavar Alireza Aliakbar Ali Mohammad-khah 《Journal of Solid State Electrochemistry》2012,16(3):869-875
A pencil graphite electrode coated by copper (II)–carmoisine dye complex in polyaniline (emeraldine base form) matrix (termed
as PGE/PA/Cu-Car) was prepared and used as copper ion-selective electrode. The introduced electrode was found to have high
selectivity toward copper ion (II) and exhibited wide working concentration range, low response time, and good shelf life.
The sensor electrode showed a linear Nernstian response over the range of 5.0 × 10−6 to 1.0 × 10−1 M with a slope of 29.7 ± 1 mV per decade change in concentration. A detection limit of 2.0 × 10−6 M was obtained. The optimum pH working range of the electrode was found to be 4.0–7.0. 相似文献
5.
D. Krstić M. Çolović M. B. Kralj P. Trebše K. Krinulović V. Vasić 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2008,82(4):663-668
The influence of malathion and its four main degradation products found in irradiated solutions (malaoxon, isomalathion, diethyl
maleate and O,O-dimethyl phosphate) on acetylcholinesterase (AChE) of free and immobilized bovine erythrocytes was investigated.
The concentration-dependent responses to malathion and related organophosphates, malaoxon and isomalathion, of both AChE bioassays
used were obtained. The IC
50 values for free and immobilized AChE (3.7 ± 0.2) × 10−4 M/(1.6 ± 0.1) × 10−4, (2.4 ± 0.3) × 10−6/(3.4 ± 0.1) × 10−6 M, and (3.2 ± 0.3) × 10−6 M/(2.7 ± 0.2) × 10−6 M were obtained in the presence of malathion, malaoxon and isomalathion, respectively. However, diethyl maleate inhibited
AChE activity at concentrations ≥ 10 mM, while O,O-dimethyl phosphate did not noticeably affect enzyme activity at all investigated
concentrations. The relation between the structure of the compounds and their ability to inhibit enzyme activity was discussed.
The article is published in the original. 相似文献
6.
A. R. Joshi Nijith Sebastian K. G. Kate D. R. Ghadse 《Journal of Radioanalytical and Nuclear Chemistry》2010,286(1):115-119
Coated wire ion selective electrode for thorium ion selective potentiometry was developed. Thorium ion selective coated wire
electrodes were prepared by depositing a membrane comprising of Aliquat-336 loaded with Th(NO3)62− ions and poly vinyl chloride in varying proportion. A linear near-Nernstian response with a slope of −29.5 ± 0.3 mV over
thorium concentration range of 1 × 10−1–3 × 10−5 M in constant total nitrate concentration of 6 M was obtained for the electrodes of almost all the composition studied. In
spite of small drift in response potential from composition to composition, day to day as well as from electrode to electrode,
the slope of potential response line was constant within experimental error. Moreover, the electrode once prepared could be
conveniently used over a period of one and half month. 相似文献
7.
Ashok Kumar Singh Ravindra Pratap Singh Sameena Mehtab 《Journal of inclusion phenomena and macrocyclic chemistry》2008,60(1-2):9-15
A new polystyrene based membrane electrode of methyl substituted 6,7:13,14-dibenzo-2,4,9,11-tetraphenyl-1,5,8,12-tetraazacyclotetradeca-1,4,6,8,11,13-hexaene
(I) with sodium tetraphenylborate (NaTPB) and dibutyl phthalate (DBP) as anion excluder and plasticizing agent was prepared and
investigated as Hg (II)-selective electrode. The electrode exhibits a Nernstian response for Hg (II) ions over a wide concentration
range of 1.0 × 10−1–8.9 × 10−6 M with a slope of 30 ± 1 mV per decade concentration. It has a response time of 10 s and can be used for at least 4 months
without any divergence in potentials. The membrane works satisfactorily in a partially non-aqueous medium up to a maximum
30% (v/v) content of methanol and ethanol. The proposed sensor revealed good selectivity over a wide variety of other cations
including alkali, alkaline earth, heavy and transition metal ions and could be used in a pH range of 2.5–5.0. Normal interferents
like Ag+, Cd2+ and Pb2+ low interfere in the working of the electrode. The electrode was successfully used in the direct determination of Hg2+ in aqueous solution. 相似文献
8.
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
9.
Newly developed, simple, low-cost and sensitive ion-selective electrodes have been proposed for determination of some antiepileptic
drugs such as lamotrigine, felbamate, and primidone in their pharmaceutical preparations as well as in biological fluids.
The electrodes are based on poly(vinyl chloride) membranes doped with drug–tetraphenyl borate (TPB) or drug–phosphotungstic
acid (PT) ion-pair complexes as molecular recognition materials. The novel electrodes displayed rapid Nernstian responses
with detection limits of approximately 10−7 M. Calibration graphs were linear over the ranges 5.2 × 10−7–1.0 × 10−3, 1.5 × 10−6–1.0 × 10−3, and 2.6 × 10−7–1.0 × 10−3 M for drug–TPB and 5.8 × 10−7–1.0 × 10−3, 1.8 × 10−7–1.0 × 10−3, and 6.6 × 10−7–1.0 × 10−3 M for drug–PT electrodes, respectively, with slopes ranging from 52.3 to 62.3 mV/decade. The membranes developed have potential
stability for up to 1 month and proved to be highly selective for the drugs investigated over other ions and excipients. The
results show that the selectivity of the ion-selective electrodes is influenced significantly by the plasticizer. The proposed
electrodes were successfully applied in the determination of these drugs in pharmaceutical preparations in four batches of
different expiry dates. Statistical Student’s t test and F test showed insignificant systematic error between the ion-selective electrode methods developed and a standard method. Comparison
of the results obtained using the proposed electrodes with those found using a reference method showed that the ion-selective
electrode technique is sensitive, reliable, and can be used with very good accuracy and high percentage recovery without pretreatment
procedures of the samples to minimize interfering matrix effects.
Figure Structure of lamotrigine, felbanate and primidone 相似文献
10.
M. Mazloum Ardakani P. Ebrahimi M. R. Mansournia 《Russian Journal of Electrochemistry》2008,44(9):1065-1072
A new salicylate-selective electrode based on the complex (2,3;6,7;10,11;14,15-tetraphenyl-4,9,13,16-tetraoxo-1,5,8,12-tetraazacyclohexadecane)
copper(II) [CuL] as the membrane carrier was developed. The electrode exhibits a good Nernstian slope of −60.9 ± 1.0 mV/decade
and a linear range from 1.0 × 10−6 to 1.0 × 10−1 M for salicylate. The detection limit is 5.0 × 10−7 M. The electrode has a fast response time (5–15 s) and can be used for more than three months. The selective coefficients
were determined by the fixed interference method (FIM) and separate solution method (SSM). The salicylate-selective electrode
could be used in the pH range 3.5–10.5. It was employed as an indicator electrode for direct determination of salicylate in
pharmaceutical samples.
Published in Russian in Elektrokhimiya, 2008, Vol. 44, No. 9, pp. 1147–1154.
The text was submitted by the authors in English. 相似文献
11.
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
12.
Slobodan Brinić Marijo Buzuk Marija Bralić Eni Generalić 《Journal of Solid State Electrochemistry》2012,16(4):1333-1341
The development of Cu(II) solid-contact ion-selective electrodes, based on 1,2-di-(o-salicylaldiminophenylthio)ethane as a neutral carrier, is presented. For the electrodes construction, unmodified carbon ink
(type 1 electrode) and polymer membrane-modified carbon ink (type 2 electrode) were used as solid support and transducer layer.
Also, carbon ink composite polymer membrane electrode (type 3 electrode) was prepared. The analytical performance of the electrodes
was evaluated with potentiometry, while bulk and interfacial electrode features were provided with electrochemical impedance
spectroscopy. It is shown that modification of carbon ink with polymer membrane cocktail decreases the bulk contact resistance
of the transducer layer and polymer membrane, thus enhancing the analytical performance of the electrode in terms of sensitivity,
linear range, and stability of potential. The optimized electrodes of types 2 and 3 exhibit a wide linear range with detection
limits of 1.8 × 10−6 and 1.6 × 10−6 M, respectively. They are suitable for determination of Cu2+ in analytical measurements by direct potentiometry and in potentiometric titrations, within pH between 2.3 and 6.5. The electrodes
are selective for Cu2+ over a large number of tested transition and heavy metal ions. 相似文献
13.
de la Escosura-Muñiz A González-García MB Costa-García A 《Analytical and bioanalytical chemistry》2006,384(3):742-750
A new electroactive label has been used to monitor immunoassays in the determination of human serum albumin (HSA) using glassy-carbon
electrodes as supports for the immunological reactions. The label was a gold(I) complex, sodium aurothiomalate, which was
bound to rabbit IgG anti-human serum albumin (anti-HSA-Au). The HSA was adsorbed on the electrode surface and the immunological
reaction with gold-labelled anti-HSA was then performed for one hour by non-competitive or competitive procedures. The gold(I)
bound to the anti-HSA was electrodeposited in 0.1 mol L−1 HCl at −1.00 V for 5 min then oxidised in 0.1 mol L−1 H2SO4 solution at +1.40 V for 1 min. Silver electrodeposition at −0.14 V for 1 min followed by anodic stripping voltammetry were
then performed in aqueous 1.0 mol L−1 NH3–2.0×10−4 mol L−1 AgNO3. For both non-competitive and competitive formats, calibration plots in the ranges 5.0×10−10 to 1.0×10−8 mol L−1 and 1.0×10−10 to 1.0×10−9 mol L−1 HSA, respectively, with estimated detection limits of 1.5×10−10 mol L−1 (10 ng mL−1) and 1.0×10−10 mol L−1 (7 ng mL−1), respectively, were obtained. Levels of HSA in two healthy volunteer urine samples were also evaluated, using both immunoassay
formats. 相似文献
14.
M. Soledad García Joaquín Ortuño M. Isabel Albero María Cuartero 《Analytical and bioanalytical chemistry》2009,394(6):1563-1567
A trazodone-selective electrode for application in pharmaceutical quality control and urine analysis was developed. The electrode
is based on incorporation of a trazodone-tetraphenylborate ion exchanger in a poly(vinyl chloride) membrane. The electrode
showed a fast, stable and Nernstian response over a wide trazodone concentration range (5 × 10−5−1 × 10−2 M) with a mean slope of 59.3 ± 0.9 mV/dec of concentration, a mean detection limit of 1.8 × 10−5 ± 2.2 × 10−6 M, a wide working pH range (5–7.5) and a fast response time (less than 20 s). The electrode also showed good accuracy, repeatability,
reproducibility and selectivity with respect to some inorganic and organic compounds, including the main trazodone metabolite.
The electrode provided good analytical results in the determination of trazodone in pharmaceuticals and spiked urine samples;
no extraction steps were necessary. Dissolution testing of trazodone tablets, in different conditions of pH and particle size,
based on a direct potentiometric determination with the new selective electrode is presented as well. 相似文献
15.
The polarographic reduction of Co(II) in the presence of moxifloxacin (1-cyclopropyl-7-[(S,S)-2.8-diazabicyclo[4.3.0]non-8-yl]-6-fluoro-8-methoxy-1.4-dihydro-4-oxo-3-quinolinecarboxylic
acid) gives rise to an additional adsorption peak corresponding to the reduction of Co(II)-moxifloxacin complex on the mercury
drop electrode at −1.17 V. This new peak is applicable to Co(II) determination with the linearity proportional to the Co(II)
concentration in the range of 4.93 × 10−7−6.90 × 10−5 M and can be attributed to an adsorption-controlled process with an irreversible reduction. Without using moxifloxacin, the
polarographic determination of 2.50 × 10−6 M Co(II) is impossible under the given conditions due to very poor sensitivity at −1.38 V. The proposed method showed good
precision and accuracy with a relative standard deviation of 3.01% and relative error of +6.40% for the determination of 2.50
× 10−6 M Co(II) next to 5.0 × 10−6 M of Zn(II), Ni(II), and Cd(II). The accuracy of the method was also checked by the determination of Co(II) spiked with tap
water and certified sea water, and the percentage recoveries were 97.5 and 96.7%, respectively (n = 4 at 95% confidence interval).
The text was submitted by the authors in English. 相似文献
16.
Magda M. Ayad Abdalla Shalaby Hisham E. Abdellatef Heba M. Elsaid 《Mikrochimica acta》2002,140(1-2):93-96
The construction of a plasticised PVC matrix-type promazinium cation-selective membrane electrode and its use in the potentiometric
determination of promazine hydrochloride in pharmaceutical preparations are described. It is based on the use of the ion-associate
species, formed by promazinium cation and tetraphenylborate (TPB) counter ion. The basic electrode performance characteristics
are evaluated according to IUPAC recommendations. It exhibited a linear response for 1 × 10−2−1 × 10−5 M of promazine hydrochloride solutions with a cationic Nernstian slope over the pH range 2–6. Common organic and inorganic
cations showed negligible interference. Direct potentiometric determination of 1 × 10−2−1 × 10−5 M aqueous promazine hydrochloride using this membrane electrode system showed an average recovery of 99.5% with a mean standard
deviation of 1.5%. This electrode was successfully used for monitoring the titration of promazine hydrochloride with sodium
tetraphenyl borate and for determining promazine hydrochloride in ampoules.
Received June 15, 2001 Revision November 6, 2001 相似文献
17.
Won-Sik Han Young-Hoon Lee Soon-Nyeo Lee Tae-Kee Hong 《Journal of Analytical Chemistry》2011,66(9):854-858
Iodide ion selective poly(aniline) solid contact electrode based on quinine-Cu ionophore as a sensing material has been successfully
developed. The electrode exhibits good linear response of 52.0 mV/decade (at 20 ± 0.2°C, r
2 = 0.9998) within the concentration range of 1 × 10−6.4–1 × 10−1.0 M KI. The composition of this electrode was quinine-Cu 2.0: PVC 30.0: bis(2-ethylhexyl)sebacate 68.0 (mass). This plasticizer
provides the best response characteristics. The electrode shows good selectivity for iodide ion in comparison with any other
anions and is suitable for use with aqueous solutions of pH 3.3–9.4. The standard deviations of the measured EMF difference
were ±1.4 and ±1.3 mV for iodide sample solutions of 1.0 × 10−2 M and 1.0 × 10−3 M, respectively. The stabilization time was less than 10 min and response time was less than 15 sec. 相似文献
18.
V. S. Rodgher L. L. Okumura A. A. Saczk N. R. Stradiotto M. V. B. Zanoni 《Journal of Analytical Chemistry》2006,61(9):889-895
The voltammetric reduction of acetaldehyde was studied in 0.1 M LiOH: LiCl (60: 40 v/v). Well-defined waves can be seen at
−1.77 and −1.60 V with the use of hanging mercury and glassy carbon electrodes. Acetaldehyde was shown to react at room temperature
with the 2,4-dinitrophenylhydrazine and the product exhibited a differential pulse voltammetric peak at −0.90 V, which was
well separated from the peaks of the derivative. This allowed the indirect determination of acetaldehyde in the presence of
0.1 M ethanol/tetrabutylammonium perchlorate after 10 min of reaction. Calibration graphs were obtained for 1.00 × 10−6−1.00 × 10−4 M of acetaldehyde. The detection limit is 8.14 × 10−7 M. The method has been applied satisfactorily to the determination of total aldehyde in fuel ethanol samples without any
pretreatment.
The text was submitted by the authors in English. 相似文献
19.
Electrochemical detection of copper(II) at a gold electrode modified with a self-assembled monolayer of penicillamine 总被引:1,自引:0,他引:1
A penicillamine (PCA) self-assembled monolayer (SAM) was prepared on a gold electrode. It has been found that the modified
electrode exhibited a selective response to copper ions. As demonstrated by cyclic voltammetric experiments, the SAM-based
electrode showed an attractive ability to preconcentrate efficiently traces of copper(II) from solutions. Under optimum conditions,
the anodic peak current was proportional to the concentration of Cu(II) in the range from 8.0 × 10−7 to 1.0 × 10−4 M with a detection limit of 4.0 × 10−7 M. Moreover, this modified gold electrode is also characterized by excellent repeatability, showing a relative standard deviation
of 3.2% for nine successive measurements of 1.0 × 10−5 M Cu(II). The PCA/Au SAM gold electrode was used for the determination of Cu(II) in a tap water sample and the results showed
a good agreement with the data obtained by atomic emission spectrometry.
The text was submitted by the authors in English. 相似文献
20.
A catalytic adsorptive stripping voltammetric method for the determination of copper(II) on a carbon paste electrode (PCE)
in an alizarin red S (ARS)-K2S2O8 system is proposed. In this method, copper(II) is effectively enriched by both the formation and adsorption of a copper(II)-ARS
complex on the PCE, and is determined by catalytic stripping voltammetry. The catalytic enhancement of the cathodic stripping
current of the Cu(II) in the complex results from a redox cycle consisting of electrochemical reduction of Cu(II) ion in the
complex and subsequent chemical oxidation of the Cu(II) reduction product by persulfate, which reduces the contamination of
the working electrode from Cu deposition and also improves analytical sensitivity. In Britton-Robinson buffer (pH 4.56±0.1)
containing 3.6×10−5 mol L−1 ARS and 1.6×10−3 mol L−1 K2S2O8, with 180 s of accumulation at −0.2 V, the second-order derivative peak current of the catalytic stripping wave was proportional
to the copper(II) concentration in the range of 8.0×10−10 to ∼3.0×10−8 mol L−1. The detection limit was 1.6×10−10 mol L−1. The proposed method was evaluated by analyzing copper in water and soil. 相似文献