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1.
A new sulfate-selective electrode based on the complex N,N'-bis(2-amino-1-oxo-phenelenyl)phenylenediamine copper(II) (CuL) as the membrane carrier was developed. The electrode exhibited a good Nernstian slope of -29.5 +/- 0.5 mV/decade and a linear range of 1.0 x 10(-7) - 1.0 x 10(-1) M for sulfate. The limit of detection was 1.0 x 10(-8) M. It has a fast response time of 10 s and can be used for more than three months. The selective coefficients were determined by the fixed interference method (FIM). The electrode could be used in the pH range 3.5 - 8.0. It was employed as an indicator electrode for direct determination of sulfate in pharmacy and cement samples.  相似文献   

2.
A strontium Schiff's base complex (SS) can be used as a suitable ionophore to prepare a sulfate-selective PVC-based membrane electrode. The use of oleic acid (OA) and hexadecyltrimethylammonium bromide (HTAB), as additives, and nitrobenzen (NB), dibutyl phthalate (DBP) and benzyl acetate (BA) as solvent mediators, were investigated. The best performance was observed with a membrane composition PVC: NB: SS: HTAB of 30%: 62%: 5%: 3% ratio. The resulting sensor works well over a wide concentration range (1.0 x 10(-2)-1.0 x 10(-6) M) with a Nernstian slope of -29.2 mV per decade of sulfate activity over a pH range 4.0-7.0. The limit of detection of the electrode is 5 x 10(-7) M. The proposed sensor shows excellent discriminating ability toward SO4(2-) ions with regard to many anions. It has a fast response time of about 15 s. The membrane electrode was used to the determination of zinc in zinc sulfate tablets. The sensor was also used as an indicator electrode in the potentiometric titration of SO4(2-) against barium ion.  相似文献   

3.
A poly(vinyl chloride)-based membrane of 3,4:11,12-dibenzo-1,6,9,14-tetraazacyclohexadecane with sodium tetraphenyl borate (NaTPB) as an anion excluder and dibutylphthalate (DBP), dibutyl(butyl)phosphonate (DBBP), tris(2-ethylhexyl)phosphate (TEHP) and tributyl phosphate (TBP) as a plasticizing solvent mediator was prepared and investigated as a Cd2+-selective electrode. The best performance was observed with the membrane having a ligand-PVC-DBP-NaTPB composition of 2:25:60:1, which worked well over a wide concentration range (1.6 x 10(-6) - 1.0 x 10(-1) M) with a Nernstian slope of 29.5 mV per decade of activity between pH 2.0 - 6.0. This electrode showed a fast response time of 13 s and was used over a period of 4 months with good reproducibility (S = 0.4 mV). The selectivity coefficient for mono-, di- and trivalent cations indicated excellent selectivity for Cd2+ ions over a large number of cations. Anions such as NO3- and SO4(2-) , did not interfere. The membrane sensor has been successfully used to determine Cd2+ in real samples.  相似文献   

4.
A new solid-contact Ag+-selective electrode was prepared with 9,10,12,13,24,25-hexahydro-5H,15H,23H-dibenzo [b,q][1,7,10,13,19,4,16]-entathiadiazacyclodocosine-6,16(7H,17H)-dione as ionophore,and cc,a>-dihexylsexithiophene(DH- 6T) ion-to-electron transducer.The sensor exhibited a working concentration range of 108 to 10-3 mol/L,with a near-Nernstian slope of 55.1±0.2 mV/dec and detection limit of 1.7×10-9 mol/L.The fabricated electrodes demonstrated excellent selectivity over the most common monovalent and divalent cations.  相似文献   

5.
Singh AK  Saxena P 《Talanta》2005,66(4):993-998
A new highly Tl(I)-selective PVC membrane electrode based on tetrathia macrocycle 6,7: 14,15-dibenzo-5,8,13,16-tetraoxo-1,4,9,12-tetrathiacyclohexadecane [Bz2O4(16)aneS4] (I) as membrane carrier, o-nitrophenyloctyl ether (o-NPOE) as solvent mediator and potassium tetrakis(p-chlorophenyl)borate (KTpClPB) as lipophilic additive has been developed. The best performance was given by the membrane of macrocycle (I) with composition 3:120:1.5:50 (I:o-NPOE:KTpClPB:PVC). This electrode exhibits a Nernstian response to Tl(I) ions in the concentration range 1.0 × 10−1-2.23 × 10−6 M with a slope of 58.2 mV/decade of concentration and a detection limit of 1.58 × 10−6 M. The response time of the sensor is 12 s and can be used over a period of 4 months with good reproducibility. The proposed electrode revealed good selectivity over a wide variety of other cations including alkali, alkaline earth, heavy and transition metals. The electrode works well over a pH range of 3.2-11.5 and in partially non-aqueous medium with up to 30% organic content. The sensor was also used as an indicator electrode in potentiometric titration of Tl(I) ions with KI solution.  相似文献   

6.
A highly selective electrode for iodide ion based on a thiopyrilium derivative as an excellent ionophore is described. At pH 5.5-8.0, the electrode responds to iodide ion in a linear range from 1.0×10−1 to 8.0×10−7 M with a slope of 60.2 mV per decade, and a detection limit of 2.0×10−7 M. Selectivity coefficients determined with the match potential method (MPM) indicate that the interference from inorganic and organic anions is very small. The proposed sensor shows a fast response time of approximately 15 s. It was applied as an indicator electrode in titration of iodide with Ag+.  相似文献   

7.
A new sensor to quantitatively sense aluminum in real sample conditions is presented that uses the potentiometric ion selective electrodes. Aluminum is a cation that plays an important role in the environmental process. This approach is proposed to determine aluminum levels in real samples in the required range (10?6–10?2 M). Carbon paste electrode (CPE) is introduced here as a potentiometric sensor to measure free concentration of aluminum ion. Octaethylporphyrin (OEP) acts as a selective aluminum recognition agent in the CPE. The suitable selectivity coefficient is obtained for the CPEs compare to interfering cation. The Nernstian slope and detection limit are achieved 18.4 mV/decade and 2.5 × 10?6 M Al3+, respectively. Finally, the proposed method is applied to determine aluminum concentration in real water samples and the result of this method is in agreement with the result of atomic absorption spectroscopy (AAS).  相似文献   

8.
New PVC membrane ion selective electrodes based on 1,3,5-Tris(8-quinolinoxymethyl)-2,4,6-trimethylbenzene (MO8HQ) are reported. The basic sensing material belongs to the group of tripodal ionophores. Also their derivatives prepared by placing suitable substitutents at fifth position of 8-oxine moiety, i.e, 1,3,5-Tris(5-chloro-8-quinolinoxymethyl)-2,4,6-trimethylbenzene (5CHQ), 1,3,5-Tris(5-benzoyl-8-quinolinoxymethyl)-2,4,6-trimethylbenzene (5BHQ) and 1,3,5-Tris[(5-phenylhydroxymethylene)-8-quinolinoxymethyl]-2,4,6-trimethylbenzene (HYD-8HQ) ionophores have also been used to make copper-selective membrane electrodes. Among all the four electrodes, MO8HQ and HYD-8HQ ionophores based electrodes show excellent response towards Cu (II) ions. The electrodes having composition 33% PVC, 4% MO8HQ and 63% dibutyl phthalate (DBP) and 33% PVC, 6% HYD-8HQ, 63% dibutyl phthalate (DBP) exhibit a good Nernstian response to Cu (II) ions in the range of 1.0 × 10−6 to 1 × 10−1 M. The electrode shows a reasonably fast response time of 15 s. The effect of pH and electrode response is also reported. It shows good selectivity for Cu (II) ions in comparison to heavy metal ions, transition metal ions and for alkali and alkaline earth metal ions. The electrode response and selectivity remains unchanged for at least 5 months. The electrode can be used as an indicator electrode in the potentiometric titration of Cu (II) ions with EDTA.  相似文献   

9.
10.
A mercury(II) ion selective poly(aniline) solid contact electrode based on 2-mercaptobenzimidazol (2MBI) ionophore as a sulfur containing sensing material was successfully developed. The electrode exhibits a good linear response of 29.1 mV/decade (at 20 ± 0.2°C, r 2 = 0.997) within the concentration range of 1 × 10?2?1 × 10?7 M Hg(II). The composition of this electrode was: ionophore 0.100, polyvinylchloride (PVC) 0.330, dibutylphthalate (DBP) 0.470, potassiumtetrakis(4-chlorophenyl)borate (KTpCIPB) 0.090, and oleic acid (OA) 0.010. A poly(aniline) solid contact electrode based on 2MBI with DBP and OA plasticizers exhibited the best response characteristics of the results obtained for similarly coated wire type electrodes and solid contact electrodes based on only one DBP plasticizer. The electrode shows good selectivity for mercury(II) ions in comparison with alkali, alkaline earth, transition and heavy metal ions. This electrode is suitable for use with aqueous solutions of pH 3.3?C8.0 and the standard deviation in the measured EMF difference was ±0.5 mV in a mercury nitrate sample solution of 1.0 × 10?2 M and ±1.1 mV in a mercury nitrate sample solution of 1.0 × 10?3 M. The stabilization time was less than 15 min and the response time was less than 33 s. The electrode was applied as a sensor for the determination of Hg(II) content in a sea water sample and some amalgam alloys. The results show good correlation with data obtained by atomic absorption spectrometry.  相似文献   

11.
The suitability of a xanthone derivative, 1-hydroxy-3-methyl-9H-xanthen-9-one (HMX) as a neutral ionophore for the preparation of a polyvinylchloride (PVC) membrane electrode for aluminum(III) ions was investigated. The prepared electrode exhibits a Nernstian response for Al3+ ions over a wide concentration range (1.0 × 10−6 to 1.6 × 10−1 M) with a limit of detection 6.0 × 10−7 M. It has a relatively fast response time and can be used for at least three months without any considerable divergence in potentials. The proposed membrane electrode revealed very good selectivity for Al3+ ions over a wide variety of other cations and could be used at a working pH range of 3.0-8.5. It was used as an indicator electrode in potentiometric titration of aluminum ions with EDTA and in the determination of Al3+ in different real samples.  相似文献   

12.
We have developed a highly La(III)-selective PVC membrane electrode based on a hexaaza macrocycle, 8,16-dimethyl-6,14-diphenyl-2,3,4:10,11,12-dipyridine-1,3,5,9,11,13-hexaazacyclohexadeca-3,5,8,11,13,16-hexaene [Bzo2Me2Pyo2(16)-hexaeneN6] (I) as membrane carrier, dibutylbutyl phosphonate (DBBP) as solvent mediator and sodium tetraphenylborate (NaTPB) as lipophilic additive. The best performance was given by the membrane of macrocycle I having a composition 10:260:5:120 (I:DBBP:NaTPB:PVC). The electrode exhibits a Nernstian response to La(III) ion in the concentration range 1.0x10(-1)-7.94x10(-7) M with a slope of 19.8+/-0.2 mV/decade of concentration and a detection limit of 5.62x10(-7) M. The response time of the sensor is 12 s and it can be used over a period of 4 months with good reproducibility. The electrode works well over a pH range of 2.5-10.0 and in partially non-aqueous medium with up to 30% organic content. The sensor was also used as an indicator electrode in potentiometric titration of La(III) ions with EDTA and for determining La(III) concentration in real samples.  相似文献   

13.
An ion-channel sensor was demonstrated by immobilizing ETH 1001, an ionophore for ion-selective electrodes, on a gold electrode surface. The approach for preparing the sensor was to incorporate the ionophore into a mixed self-assembled monolayer of 10-mercaptodecanesulfonate and 11-hydroxy-1-undecanethiol formed on the surface. The voltammetric responses for the thus prepared sensor to the primary cation Ca(2+) were observed by using [Fe(CN)(6)](3-/4-) as an electroactive marker. The ionophore was stably immobilized on the electrode surface with the hydrophobic interaction between its alkyl chains and those of the alkanethiol. The introduction of a proper charge density to the electrode surface improved the sensor sensitivity with retaining the selective response to Ca(2+) against Mg(2+) with concentrations above 10(-4) M.  相似文献   

14.
The Na+ transporting properties of the first member of a new class of artificial ionophores, based on a C2-symmetric polyhydroxylated steroid dimer, are described.  相似文献   

15.
Pankaj Kumar 《Talanta》2010,82(4):1107-1112
An all-solid-state electrode, containing a synthesized chiral A2B2 macrocyclic compound namely (4R,5R,15R,16R)-4,5,15,16-tetraphenyl-3,6,14,17-tetraazatricyclo [13.3.1.18,12] tetracosa-1(23),8,10,12(24)19,21-hexaene-2,7,13,18-tetrone as an ionophore in polyvinyl chloride (PVC)/polyurethane (PU) membrane matrix, has been developed for the selective quantification of monohydrogen phosphate ions. The best performing membrane contained PVC, PU, ionophore, and nitrophenyl octyl ether as a plasticizer in the ratio 32.2:2.6:65.1 (w/w, %). It exhibited a near-Nernstian slope of 31.0 ± 1.0 mV/decade of activity for HPO42− ions in the concentration range of 1.0 × 10−6 to 1.0 × 10−2 M at pH 7.4. The detection limit of the electrode was 8.4 × 10−7 M and the life time was six weeks. The electrode displayed excellent selectivity for monohydrogen phosphate over other anions and the selectivity sequence was determined as HPO42− > SO42− > Ac > NO3 > ClO4 > Cl > I. The selective electrode for the monohydrogen phosphate ions was evaluated with a standard reference material (SRM 1548) and the titration of the sample solution.  相似文献   

16.
An optical strip test to determine calcium is proposed. The membrane consists of a polyester sheet and an active layer composed of a cation-selective neutral ionophore, such as 18-crown-6-ether, a proton selective neutral chromoionophore, such as lipophilised Nile Blue, and potassium tetrakis(4-chlorophenyl)borate as a lipophilic salt. The membrane responds reversibly to calcium ions by an ion-exchange mechanism, changing its colour from blue to red. All experimental variables that influence test strip response, especially in terms of selectivity and response time, have been studied. The system responded linearly in activities in the range 0.046-134 mM. The detection limit is 0.046 mM, the reproducibility intermembrane at a medium level of the range was 8.5%, as relative standard deviation (R.S.D.) of logaCa2+ and 2.7% as intramembrane.Calcium was determined by using the test strip proposed in different types of waters (tap, mineral and spring) validating results against a reference procedure. This proposed method for calcium determination in waters is quick (less than 5 min), inexpensive, selective and sensitive and uses only conventional instrumentation.  相似文献   

17.
Hydrogen-ion selective solid contact electrodes based on tribenzylamine, dibenzylnaphthalenemethylamine, and dibenzylpyrenemethylamine ionophores were prepared. With these electrodes, we showed that the response ranges were influenced by the number of phenyl rings in the ionophores. The lower limits for a linear pH response in acidic solutions were pH 2.50, 0.65, and 0.50, respectively. As the number of phenyl rings in the ionophores increased, the slopes of the EMF responses of these electrodes did not change significantly, but their response extended toward an acidic range (shifted to pH 0.50). Thus, their dynamic response range became wider. A solid contact electrode with dibenzylpyrenemethylamine ionophore, in particular, showed the best selectivity, from the interference of cations and anions, and the best reproducibility of the EMF. This electrode was stored in Tris buffer solutions, artificial serum, and hydrofluoric acid solutions for one month without any loss of performance. Their response time was 8 s. Satisfactory results were obtained when it was tested directly with artificial serum (in pH range 6.0 - 8.5) and hydrofluoric acid.  相似文献   

18.
The feasibility of a metal palladium electrode as the pH sensor in air-saturated aqueous solutions was evaluated. The measurement was based on an “on-site” precleaning step and a potential decay process. The experimental results showed a linear pH response with a sensitivity of around 60 mV/pH and good reproducibiliry. The temperature effect on the measurement was also evaluated.  相似文献   

19.
A new PVC membrane based strontium(II) ion-selective electrode has been constructed using acetophenone semicarbazone as a neutral carrier. The sensor exhibits a Nerstian response for strontium(II) ion over a wide concentration range 1.0 × 10−2–1.0 × 10−7 M with the slope of 29.4 mV/per decade. The limit of detection was 2.7 × 10−8 M. It was relatively fast response time (<10 s for concentration ⩾1.0 × 10−3 and <15 s for concentration of ⩾1.0 × 10−6 M) and can be used for 8 months without any considerable divergence in potentials. The proposed sensor revealed relatively good selectivity and high sensitivity for strontium(II) over a mono, di, trivalent cation and can be used in a pH range of 2.5–10.5. It was also successfully used as an indicator electrode in potentiometer titration and in the analysis of concentration in various real samples.  相似文献   

20.
A hydrogen ion-selective solid-contact electrode based on N,N,N',N'-tetrabenzylethanediamine has shown the best Nernstian slope and selectivity and the widest response range in a Tris buffered pH sample solution. Its linear dynamic range was pH 3.50-11.94, and the Nernstian slope showed 52.1 mV/pH (at 20 +/- 0.2 degrees C). When it was directly applied to human whole blood (in pH range 6.0-8.5) we could obtain the same satisfying results. This electrode continuously contacted a Tris 7.47 buffered solution, human whole blood and a hydrofluoric acid solution for one month without any loss of performance. Also, hydrofluoric acid did not influence the surface of this electrode, and thus it was maintained without showing any changes in potentials after being used in a hydrofluoric acid solution. The standard deviation in the determined e.m.f. differences was 1.5 mV (N = 5) for Tris buffer solutions of pH 6.5 and 1.1 mV at a Tris buffer solutions of pH 8.5. The 90% response time of the electrodes obtained by injecting of hydrochloric acid into the Tris buffer sample solution was less than 10 s. Especially, in the this paper, with these potential response characteristics of hydrogen ion selective poly(aniline) solid contact electrode, we have also presented the pH response mechanism of this electrode and the role of poly(aniline) and a doped anion in a poly(aniline) layer.  相似文献   

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