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1.
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
2.
Sayed S. Badawy Yousry M. Issa Waheed F. El-Hawary Manal S. Ashour 《Mikrochimica acta》2001,136(1-2):1-7
A PVC membrane electrode selective for cetyldimethylethylammonium (CDEA) ion was prepared. The active element is a plasticized
poly vinyl chloride membrane containing a dissolved ion associate complex of CDEA with phosphotungstic acid (PTA). The electrode
showed a near-Nernstian response within the CDEA+ concentration range 2.34 × 10−6 to 1.96 × 10−4 M at 25 ± 1^C, good selectivity, and is usable within the pH range 3.5–9.0. The isothermal temperature coefficient of the electrode amounted
to −0.00012 V/°C. The electrode has been used for the direct determination of cetyldimethylethylammonium bromide either by
the standard addition method or by potentiometric titration against PTA.
Received January 1, 1998. Revision June 13, 2000. 相似文献
3.
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
4.
The electrode characteristics and selectivities of PVC-based thiocyanate selective polymeric membrane electrode (PME) incorporating
the newly synthesized zinc complex of 6,7:14,15-Bzo2-10,11-(4-methylbenzene)-[15]-6,8,12,14-tetraene-9,12-N2-1,5-O2 (I
1
) and zinc complex of 6,7:14,15-Bzo2-10,11-(4-methylbenzene)-[15]-6,14-diene-9,12-dimethylacrylate-9,12-N2-1,5-O2 (I
2
) are reported here. The best response was observed with the membrane having a composition of I2:PVC:o-NPOE:HTAB in the ratio of 6:33:59:2 (w/w; milligram). This electrode exhibited Nernstian slope for thiocyanate ions over working concentration range of 4.4 × 10−7 to 1.0 × 10−2 mol L−1 with detection limit of 2.2 × 10−7 mol L−1. The performance of this electrode was compared with coated graphite electrode (CGE), which showed better response characteristics
w.r.t Nernstian slope 59.0 ± 0.2 mV decade−1 activity, wide concentration range of 8.9 × 10−8 to 1.0 × 10−2 mol L−1 and detection limit of 6.7 × 10−8 mol L−1. The response time for CGE and PME was found to be 8 and 10 s, respectively. The proposed electrode (CGE) was successfully
applied to direct determination of thiocyanate in biological and environmental samples and also as indicator electrode in
potentiometric titration of SCN− ion. 相似文献
5.
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
6.
Conducting polymer poly(pyrrole) (PPy) doped with Nafion was successfully used as ion-to-electron transducer in the construction
of a solid-contact Pb2+-selective polymeric membrane electrode. The Nafion dopant can effectively increase the capacitance of the conducting polymer
and improve the mechanical robustness of the coating. The transducer layer, PPy-Nafion, characterized by cyclic voltammetry
and electrochemical impedance spectroscopy, exhibits a sufficiently high bulk (redox) capacitance and fast ion and electron
transport process. The new Pb2+-selective polymeric membrane electrode, based on PPy-Nafion film as solid contact, shows stable Nernstian characteristics
in Pb(NO3)2 solution within the concentration range of 1.0 × 10−7–1.0 × 10−3 M, and the detection limit is 4.3 × 10−8 M. The potential stability of the electrode and the influence of the interfacial water layer were also evaluated by chronopotentiometry
and potentiometric water layer test, respectively. The results show that the solid-contact Pb2+-selective electrode, based on PPy-Nafion film as ion-to-electron transducer, can effectively overcome the potential drift
and reduce the water layer between the PPy-Nafion transducer layer and the ion-selective membrane. 相似文献
7.
Oxytetracycline hydrochloride-selective electrodes of both the coated wire and the conventional polymer membrane types based
on oxytetracyclinium phosphotungstate and phosphomolybdate have been prepared. A Nernstian response is shown by these electrodes
within 1.0×10−6–1.0×10−2 M concentration ranges depending on the type of electrode. The response is unaffected by the change of pH over the range
4–11. The standard electrode potentials, E°, were determined at different temperatures and used to calculate the isothermal
temperature coefficients of the electrodes. The electrodes show good selectivity to oxytetracycline hydrochloride with respect
to many inorganic cations, sugars and amino-acids. Oxytetracycline hydrochloride is determined successfully in pure solutions
and in pharmaceutical preparations using calibration by standard addition and potentiometric titration. A regeneration process
for the exhausted electrodes has been developed.
Received February 2, 2000. Revision April 7, 2000. 相似文献
8.
By combining the layer-by-layer (LBL) self-assembly technique with the electrochemical polymerization method, multilayer Ni(II)-polyluminol
films were modified on the surface of a vaseline-impregnated graphite electrode. It was found that, compared with an electrode
modified by direct electrochemical polymerization, this modified electrode offered a suitable ECL reaction micro-environment
created by the special multilayer films, which was beneficial to the ephedrine hydrochloride enhancing effect for luminol
ECL intensity. The ECL enhancing effect of ephedrine hydrochloride on the electro-oxidation luminol was improved on this modified
electrode. Based on this finding, a new sensitive ECL method was developed for ephedrine hydrochloride determination under
the optimal conditions. At the same time, a new idea is proposed for improving the analytical performance of the luminol ECL
system by modifying the ECL reaction micro-environment with the layer-by-layer self- assembly method. Under the optimum experimental
conditions, the ephedrine hydrochloride concentration in the range of 2.0 × 10−8–7.0 × 10−6 mol L−1 was proportional to the enhanced ECL signal, and it offered an 8.0 × 10−9 mol L−1 detection limit for ephedrine hydrochloride. 相似文献
9.
Ai-Lin Liu Jia-Dong Wang Wei Chen Xing-Hua Xia Yuan-Zhong Chen Xin-Hua Lin 《Journal of Solid State Electrochemistry》2012,16(4):1343-1351
A simple, rapid, sensitive, and accurate method for simultaneous electrochemical determination of procaine and its metabolite
(p-aminobenzoic acid, PABA) for pharmaceutical quality control and pharmacokinetic research was developed using a graphite paste
electrode. The differential pulse voltammetric results revealed that procaine and p-aminobenzoic acid, respectively, showed well-defined anodic oxidation peaks on a carbon paste electrode with a current peak
separation of 155 mV at a scan rate of 100 mV s−1. This well separation of the current peaks for these two compounds in voltammetry enables us to simultaneously determine
them. Good linearity (r > 0.998) between oxidation peak current and concentration was obtained in the range of 5.0 × 10−7–5.0 × 10−5 M for procaine and 5.0 × 10−7–2.0 × 10−5 M for PABA in pH 4.50 acetate buffer solution. The detection limit for both analytes is 5 × 10−8 M (S/N = 3:1). The present voltammetric method has been successfully used to determine trace p-aminobenzoic acid in procaine hydrochloride injection and procaine in plasma with a linear relationship of current to its
concentration ranging from 1.0 × 10−6 to 5.0 × 10−5 M (correlation coefficient of 0.9981) with a low detection limit of 5.0 × 10−7 M (S/N = 3:1). This validated method is promising to the study of pharmacokinetics in Sprague–Dawley rat and rabbit plasma after
an intravenous administration of procaine hydrochloride injection. 相似文献
10.
A. Radi 《Mikrochimica acta》1999,132(1):49-53
The electrochemical oxidation of nicergoline is investigated using cyclic and differential pulse voltammetry at a carbon
paste electrode. For the determination of nicergoline an adsorptive stripping procedure is proposed. The response is characterized
with respect to pH, ionic strength, preconcentration time, accumulation potential, nicergoline concentration, reproducibility
and other variables. By differential pulse voltammetry at a carbon paste electrode and pH 8.0, a linear calibration in the
range 5×10−8 M to 1×10−7 M and a detection limit of 1×10−8 M are obtained. The preconcentration medium-exchange approach was used for a selective determination of nicergoline in urine.
For dilute urine samples a detection limit of 5×10−8 M is obtained after 3 min of accumulation and medium-exchange. The procedure also is applied for the determination of nicergoline
in dosage form.
Received August 24, 1998. Revision April 8, 1999. 相似文献
11.
Raúl A. Sánchez-Moreno M. Jesús Gismera M. Teresa Sevilla Jesús R. Procopio 《Analytical and bioanalytical chemistry》2010,397(1):331-338
A disposable screen-printed electrode was designed and evaluated for direct detection of chromium(VI) in batch and flow analysis.
The carbon screen-printed electrode was modified with a graphite–epoxy composite. The optimal graphite–epoxy matrix contains
37.5% graphite powder, 12.5% diphenylcarbohydrazide, a selective compound for chromium(VI), and 50% epoxy resin. The principal
analytical parameters of the potentiometric response in batch and flow analysis were optimized and calculated. The screen-printed
sensor exhibits a response time of 20 ± 1 s. In flow analysis, the analytical frequency of sampling is 70 injections per hour
using 0.1 M NaNO3 solution at pH 3 as the carrier, a flow rate of 2.5 mL·min−1, and an injection sample volume of 0.50 mL. The sensor shows potentiometric responses that are very selective for chromium(VI)
ions and optimal detection limits in both static mode (2.1 × 10−7 M) and online analysis (9.4 × 10−7 M). The disposable potentiometric sensor was employed to determine toxicity levels of chromium(VI) in mineral, tap, and river
waters by flow-injection potentiometry and batch potentiometry. Chromium(VI) determination was also carried out with successful
results in leachates from municipal solid waste landfills. 相似文献
12.
A differential pulse voltammetric method for the determination of nitrate has been described, which is applicable to the
analysis of natural water samples with nitrate levels greater than 2.8 × 10−6 M. A reduction peak for the nitrate ions at a freshly copper plated glassy carbon electrode was observed at about −0.50 V
vs Ag ∣AgCl∣KClsatd electrode in a solution of 2.0 × 10−2 M Cu2+, 0.5 M H2SO4 and 1.0 × 10−3 M KCl and exploited for analytical purposes. The working linear range was established by regression analysis and found to
extend from 2.8 ×10−6 M to 8.0 × 10−5 M. The proposed method was applied for the determination of nitrate in natural waters. The detection limit of the method
was 2.8 × 10−6 M and the sensitivity was 0.9683 A·L/mol. The possible interferences by some ions such as phosphate, nitrite and some halides
were determined and found to lead to shifts of the peak position and increasing the peak heights.
Received March 15, 1999. Revision July 9, 1999. 相似文献
13.
Fathalla Belal Saadia M. El-Ashry Ihsan M. Shehata Magda A. El-Sherbeny Dina T. El-Sherbeny 《Mikrochimica acta》2000,135(3-4):147-154
A highly sensitive differential-pulse (DPP) polarographic method is described for the determination of three N-substituted
phenothiazine derivatives, chlorpromazine (CZ), promazine (PZ) and promethazine (PMZ). The method involves the use of nitrous
acid as an oxidant. Polarographically-active sulphoxides with diffusion-current constants (Id) of 2.53, 3.05 and 3.37 were
obtained for CZ, PZ and PMZ, respectively. The polarographic waves were characterized as being diffusion-controlled, irreversible
and partly affected by adsorption phenomena. All parameters affecting the oxidation process and polarographic behaviour were
optimized and incorporated into the procedure. The limiting current-concentration plots in the DPP mode were rectilinear over
the range: 0.006–0.1 mM, 0.005–0.08 mM and 0.008–0.1 mM for CZ, PZ and PMZ, respectively, with minimum detectability (S/N=3)
of 3 × 10−7 M for CZ and PZ, and 4 × 10−7 M for PMZ, respectively. The kinetic parameters of the electrode reaction, including rate constant, free energy of activation
ΔG and effect of temperature on both parameters were studied. The proposed method was successfully applied to the determination
of phenothiazines in dosage forms; the results obtained were in agreement with those given with the official methods. The
method was further applied to the determination of promazine in spiked human urine. The percentage recovery was 96.86 ± 0.30.
The advantages of the proposed method over other reported methods were discussed. A proposal of the electrode reaction was
made.
Received June 1, 1999. Revision March 10, 2000. 相似文献
14.
Ahmad Soleymanpour Bahram Garaili S. Masoud Nabavizadeh 《Monatshefte für Chemie / Chemical Monthly》2008,139(12):1439-1445
Three platinum(II) complexes were synthesized and studied to characterize their ability as an anion carrier in a PVC membrane electrode. The polymeric membrane electrodes (PME) and also coated glassy carbon electrodes (CGCE) prepared with
one of these complexes showed excellent response characteristics to perchlorate ions. The electrodes exhibited Nernstian responses to ClO4
− ions over a wide concentration range from 1.5 × 10−6 to 2.7 × 10−1 M for PME and 5.0 × 10−7 to 1.9 × 10−1 M for CGCE with low detection limits (9.0 × 10−7 M for PME and 4.0 × 10−7 M for CGCE). The electrodes possess fast response time, satisfactory reproducibility, appropriate lifetime and, most importantly,
good selectivity toward ClO4
− relative to a variety of other common anions. The potentiometric response of the electrodes is independent of the pH of the test solution in the pH range 2.0–9.0. The proposed sensors were used in potentiometric determination of perchlorate ions in mineral water and urine
samples.
Correspondence: Ahmad Soleymanpour, Department of Chemistry, Damghan Basic Science University, Damghan, Iran. 相似文献
15.
Krishnapillai Girish Kumar Remalakshmy Poduval Sareena John Pearl Augustine 《Mikrochimica acta》2006,156(3-4):283-287
A new PVC membrane sensor, which is highly selective towards Ni (II) ions, has been developed using a thiophene-derivative
Schiff base as the ionophore. The best performance was exhibited by the membrane having the composition percentage ratio of
5:3:61:31 (ionophore:NaTPB:DBP:PVC) (w/w), where NaTPB is the anion excluder, sodium tetraphenylborate and DBP is the plasticizing
agent (dibutyl phthalate). The membrane exhibited a good Nernstian response for nickel ions over the concentration range of
1.0 × 10−1–5.0 × 10−6 M (limit of detection is 1.8 × 10−6 M) with a slope of 29.5 ± 1.0 mV per decade of activity. It has a fast response time of <20 s and can be used for a period
of 4 months with good reproducibility. The sensor is suitable for use in aqueous solutions of a wide pH range of 3.2–7.9.
The sensor shows high selectivity to nickel ions over a large number of mono-, bi- and trivalent cations. It has been successfully
used as an indicator electrode in the potentiometric titration of nickel ions against EDTA and also for direct determination
of nickel content in real samples – wastewater samples from electroplating industries and Indian chocolates. 相似文献
16.
A potentiometric azide-selective sensor based on the use of iron(III) hydrotris(3,5-dimethylpyrazolyl)borate acetylacetonate
chloride [TpMe2Fe(acac)Cl] as a neutral carrier for an azide-selective electrode is reported. Effect of various plasticizers, viz. o-nitrophenyloctyl ether (o-NPOE), dioctylphthalate (DOP), dibutylphthalate (DBP), and benzylacetate (BA), and an anion excluder, hexadecyltrimethylammonium
bromide (HTAB), with [TpMe2Fe(acac)Cl] complex in poly(vinyl chloride) (PVC) were studied. The best performance was obtained with a membrane composition
of [TpMe2Fe(acac)Cl]/HTAB/DOP/PVC in a ratio of 5:2:190:100 (w/w). The sensor exhibits significantly enhanced selectivity toward azide
ions over the concentration range 6.3 × 10−7 to 1.0 × 10−2 M with a lower detection limit of 3.8 × 10–7 M and a Nernstian slope of 59.4 ± 1.1 mV decade−1. Influences of the membrane composition, pH and possible interfering anions were investigated on the response properties
of the electrode. Fast and stable response, good reproducibility, long-term stability and applicability over a wide pH range
(3.5–9.0) are demonstrated. The sensor has a response time of 14 s and can be used for at least 45 days without any considerable
divergence in the potential response. The proposed electrode shows fairly good discrimination of azide from several inorganic
and organic anions. It was successfully applied to the direct determination of azide in orange juice, tea extracts and human
urine samples. 相似文献
17.
Wei-De Zhang Bin Xu Yu-Xiang Hong Yu-Xiang Yu Jian-Shan Ye Jia-Qi Zhang 《Journal of Solid State Electrochemistry》2010,14(9):1713-1718
In this paper, an electrochemical sensor for sensitive and convenient determination of salicylic acid (SA) was constructed
using well-aligned multiwalled carbon nanotubes as electrode material. Compared to the glassy carbon electrode, the electro-oxidation
of SA significantly enhanced at the multiwalled carbon nanotube (MWCNT) electrode. The MWCNT electrode shows a sensitivity
of 59.25 μA mM−1, a low detection limit of 0.8 × 10−6 M and a good response linear range with SA concentration from 2.0 × 10−6 to 3.0 × 10−3 M. In addition, acetylsalicylic acid was determined indirectly after hydrolysis to SA and acetic acid, which simplified the
detection process. The mechanism of electrochemical oxidation of SA at the MWCNT electrode is also discussed. 相似文献
18.
A method was developed for determining selenium with a self-made ion-selective electrode was developed. This electrode was
made by using Ag2Se as electroactive material. Optimal working conditions and interferences were investigated. The electrode exhibits good
potentiometric response for Se2− ions over the concentration range from 6 × 10−7 mol · L−1 to 1 × 10−4 mol · L−1 with a Nernstian slope of 28 ± 1 mV per decade and a detection limit of about 4.5 × 10−7 mol · L−1. It was used over six months and exhibits good selectivity and sensitivity towards Se2−. The method was applied to determine selenium in biological materials. The recovery ranges between 92% and 105.5%, and the
relative standard derivation is less than 3.6% (n = 6). 相似文献
19.
A novel lidocaine ion-selective electrode is prepared, characterized and used in pharmaceutical analysis. The electrode incorporates
PVC-membrane with lidocaine-sulfathiazole ion pair complex. The influences of membrane composition, temperature, pH of the
test solution, and foreign ions on the electrode performance were investigated. The electrode showed a Nernstian response
over a lidocaine concentration range from 1.0 ×10−5 to 1.0 × 10−1 mol L−1 with a slope of 60.1 ± 0.2 mV per decade at 25°C and was found to be very selective, precise, and usable within the pH range
5–9.5. The standard electrode potentials, E
o, were determined at 10, 15, 20, 25, 30, 35 and 40°C, and used to calculate the isothermal temperature coefficient (dE
o/dT=−0.0003 V °C−1) of the electrode. However, the electrode performance is significantly decreased at temperatures higher than 45°C. The electrode
was successfully used for potentiometric determination of lidocaine hydrochloride in pharmaceutical products.
The article is published in the original. 相似文献
20.
A new highly selective terbium(III) electrode was prepared with a polymeric film doped using S-2-benzothiazolyl-2-amino-α-(methoxyimino)-4-thiazolethiol acetate as an electroactive material, benzyl acetate (BA) as a plasticizer, and potassium
tetrakis(4-chlorophenyl) borate (KTpClPB) as an anionic site in the percentage ratio 3.17:1.58:63.4:31.7 (ionophore-KTpClPB-BA-PVC,
w/w). The electrode exhibited a linear response with a near Nernstian slope of 19.5 mV/decade within the concentration range
1.5 × 10−7−1.0 × 10−2 M terbium ions, with a working pH range from 2.0 to 8.0, and a fast response time of 10 s and presented satisfactory reproducibility.
The limit of detection was 9.3 × 10−8 M. The results show that this electrode can be used in ethanol media up to 30% (v/v) concentration without interference.
It can be used for 3 months without any considerable divergence in the potentials. Selectivity coefficients for terbium(III)
with respect to many cations were investigated. The electrode is highly selective for terbium(III) ions over a large number
of monovalent, bivalent, and trivalent cations. This shows the valuable property of the proposed electrode. The stability
constant of the ionophore towards Tb3+ ions was determined with the sandwich membrane method. It was successfully used as an indicator electrode in potentiometric
determination of terbium(III) ions with EDTA and in direct determination in tap water and binary mixtures with quantitative
results. The utility of the proposed electrode was also determined in the presence of ionic and nonionic surfactants and in
the presence of fluoride ions in four pharmaceutical (mouthwash) preparations.
Figure Structure of S-2-Benzothiazolyl-2-amino-α-(methoxyimino)-4-thiazolethiol acetate 相似文献