51
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Dai J, Yuan R, Chai Y, An L, Zhong X, Liu Y, Tang D. Highly Thiocyanate-Selective PVC Membrane Electrode Based on Lipophilic Ferrocene Derivative. ELECTROANAL 2005. [DOI: 10.1002/elan.200503313] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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52
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Shahrokhian S, Jannat-Rezvani MJ. Voltammetric Studies of Propylthiouracil at a Carbon-Paste Electrode Modified with Cobalt(II)-4-chlorosalophen: Application to Voltammetric Determination in Pharmaceutical and Clinical Preparations. Mikrochim Acta 2005. [DOI: 10.1007/s00604-005-0382-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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53
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Ardakani MM, Jalayer MS, Safari J, Sadeghi Z, Zare HR. Salicylate poly(vinyl chloride) membrane electrode based on (2-[(E)-2-(4-nitrophenyl) hydrazono]-1-phenyl-2-(2-quinolyl)-1-ethanone) Cu(II). Anal Biochem 2005; 341:259-66. [PMID: 15907871 DOI: 10.1016/j.ab.2005.03.040] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2004] [Indexed: 10/25/2022]
Abstract
A new salicylate-selective electrode based on the complex of (2-[(E)-2-(4-nitrophenyl)hydrazono]-1-phenyl-2-(2-quinolyl)-1-ethanone) Cu(II) as the membrane carrier was developed. The electrode exhibited a good Nernstian slope of -59.6+/-1.0 mV/decade and a linear range of 1.0 x 10(-6) to 1.0M for salicylate. The limit of detection was 5.0 x 10(-7) M. The electrode had a fast response time of 10 s and can be used for more than 3 months. The selective coefficients were determined by the fixed interference method and could be used in the pH range of 4.0 to 10.5. The electrode was employed as an indicator electrode for direct determination of salicylate in pharmaceutical and biological samples.
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Affiliation(s)
- M Mazloum Ardakani
- Department of Chemistry, Faculty of Science, Yazd University, Yazd, Iran.
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54
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Xu L, Yuan R, Chai YQ, Fu YZ. Novel Membrane Potentiometric Thiocyanate Sensor Based on Tribenzyltin(IV) Dithiocarbamate. ELECTROANAL 2005. [DOI: 10.1002/elan.200403209] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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55
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Shahrokhian S, Jannatrezvani MJ, Khajehsharifi H. Rhodium(II) Phthalocyanine as a Selective Carrier in Thiocyanate‐Selective Membrane Electrode. ANAL LETT 2005. [DOI: 10.1081/al-200060865] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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56
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Messick MS, Krishnan SK, Hulvey MK, Steinle ED. Development of anion selective polymer membrane electrodes based on lutetium(III) porphyrins. Anal Chim Acta 2005. [DOI: 10.1016/j.aca.2005.03.049] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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57
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Dai J, Chai Y, Yuan R, An L, Liu Y, Zhong X, Tang D. Tricoordinate Schiff Base Copper(II) Complex as Neutral Carrier for Highly Selective Thiocyanate Electrode. ANAL LETT 2005. [DOI: 10.1081/al-200047759] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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58
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Xu L, Yuan R, Chai YQ, Wang XL. A novel salicylate-selective electrode based on a Sn(IV) complex of salicylal-imino acid Schiff base. Anal Bioanal Chem 2005; 381:781-7. [PMID: 15668810 DOI: 10.1007/s00216-004-2898-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2004] [Revised: 08/25/2004] [Accepted: 10/12/2004] [Indexed: 11/29/2022]
Abstract
A novel poly(vinyl chloride) membrane electrode with high selectivity toward salicylate (Sal-), based on the use of the salicylal-imino acid Schiff base dibenyl complex of Sn(IV) [Sn(IV)-SIADBen] as ionophore is described. The influence of lipophilic charged additives on the performance of the electrode was studied. The results suggested that Sn(IV)-SIADBen according to a positively-charged carrier mechanism. The influence of several other variables was investigated in order to optimize the potentiometric response and selectivity of the electrode. The electrode based on Sn(IV)-SIADBen, with 30.44 wt% PVC, 64.55 wt% plasticizer [dioctyl phthalate (DOP)], 3.81 wt% ionophore, and 1.2 wt% anionic additive exhibited a linear response for the Sal- ion over the concentration range 1.0x10(-1) to 2.5x10(-6) mol l-1, and displayed an anti-Hofmeister selectivity sequence as follows: salicylate>>perchlorate>thiocyanate>benzoate>iodide>nitrate>chloride>nitrite approximately acetate>citrate>sulfate. UV-Visible absorption spectra were used to examine the specific interaction of salicylate with the ionophore. The electrode was applied to clinical medical analysis, and the results obtained were consistent with those obtained by conventional methods.
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Affiliation(s)
- Lan Xu
- Institute of Analytical Chemistry, the College of Chemistry and Chemical Engineering, Southwest China Normal University, Chongqing 400715, People's Republic of China
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59
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Xu L, Yuan R, Fu YZ, Chai YQ. Potentiometric Membrane Electrode for Salicylate Based on an Organotin Complex with a Salicylal Schiff Base of Amino Acid. ANAL SCI 2005; 21:287-92. [PMID: 15790114 DOI: 10.2116/analsci.21.287] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A novel salicylate-selective electrode based on an organotin complex with a salicylal Schiff base of amino acid salicylaldehydeaminoacid-di-n-butyl-Sn(IV) [Sn(IV)-SAADB] as ionophore is described, which exhibits high selectivity for salicylate over many other common anions with an anti-Hofmeister selectivity sequence: Sal- >> PhCOO- > SCN- > Cl04- > I- > NO3- > NO2- > Br- > Cl- > CH3COO-. The electrode, based on Sn(IV)-SAADB, with a 30.44 wt% PVC, a 65.45 wt% plasticizer (dioctyl phthalate, DOP), a 3.81 wt% ionophore and a 0.3 wt% anionic additive is linear in 6.0 x 10(-6) - 1.0 x 10(-1) mol l(-1) with a detection limit of 2.0 x 10(-6) mol l(-1) and a slope of 62.0 +/- 1.2 mV/decade of salicylate concentration in a phosphate buffer solution of pH 5.5 at 25 degrees C. The influence on the electrode performances by lipophilic charged additives was studied, and the possible response mechanism was investigated by UV spectra. The electrode was applied to medicine analysis and the result obtained has been satisfactory.
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Affiliation(s)
- Lan Xu
- Institute of Analytical Chemistry, The College of Chemistry and Chemical Engineering, Southwest China Normal University, Chongqing 400715, PR China
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60
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Chai Y, Yuan R, Dai J, Xu L, Gui G, Sun A. Highly Salicylate‐Selective Membrane Electrode Based onN,N′‐bis‐(Furaldehyde)‐Glycine Copper(II) Complex as Neutral Carrier. ANAL LETT 2005. [DOI: 10.1081/al-200043439] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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61
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Dai JY, Chai YQ, Yuan R, Zhang YS, Liu Y, Zhong X, Tang DP. Thiocyanate-selective PVC Membrane Electrode Based on Tricoordinate Schiff Base Copper(II) Complex. CHEM LETT 2005. [DOI: 10.1246/cl.2005.62] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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62
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Shahrokhian S, Karimi M. Voltammetric studies of a cobalt(II)-4-methylsalophen modified carbon-paste electrode and its application for the simultaneous determination of cysteine and ascorbic acid. Electrochim Acta 2004. [DOI: 10.1016/j.electacta.2004.07.015] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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63
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Chai YQ, Yuan R, Xu L, Xu WJ, Dai JY, Jiang F. A highly sensitive PVC membrane iodide electrode based on complexes of mercury(II) as neutral carrier. Anal Bioanal Chem 2004; 380:333-8. [PMID: 15300355 DOI: 10.1007/s00216-004-2772-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2004] [Revised: 06/30/2004] [Accepted: 07/10/2004] [Indexed: 11/25/2022]
Abstract
A novel solvent polymeric membrane electrode based on bis(1,3,4-thiadiazole) complexes of Hg(II) is described which has excellent selectivity and sensitivity toward iodide ion. The electrode, containing 1,4-bis(5-methyl-1,3,4-thiadiazole-2-yl-thio)butanemercury(II) [Hg(II)BMTB(NO3)4], has a Nernstian potentiometric response from 2.0 x 10(-8) to 2.0 x 10(-2) mol L(-1) with a detection limit of 8.0 x 10(-9) mol L(-1) and a slope of -59.0+/-0.5 mV/decade in 0.01 mol L(-1) phosphate buffer solution (pH 3.0, 20 degrees C). The selectivity sequence observed is iodide>bromide>thiocyanate>nitrite>nitrate>chloride>perchlorate>acetate>sulfate. The selectivity behavior is discussed in terms of the UV-Vis spectrum, and the process of transfer of iodide across the membrane interface is investigated by use of the AC impedance technique. The electrode was successfully applied to the determination of iodide in Jialing River and Spring in Jinyun Mountains, with satisfactory results.
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Affiliation(s)
- Y-Q Chai
- College of Chemistry and Chemical Engineering, Chongqing Key Laboratory of Analytical Chemistry, Southwest China Normal University, Chongqing 400715, China
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64
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Shahrokhian S, Souri A. Metalophthalocyanine complexes as ion-carriers in membrane-selective electrodes for detection of thiosalicylic acid. Anal Chim Acta 2004. [DOI: 10.1016/j.aca.2004.05.037] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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65
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Shahrokhian S, Taghani A, Hamzehloei A, Reza Mousavi S. Potentiometric membrane sensors based on zirconyl(IV) phthalocyanine for detection of sulfosalicylic acid. Talanta 2004; 63:371-6. [DOI: 10.1016/j.talanta.2003.11.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2003] [Revised: 10/19/2003] [Accepted: 11/05/2003] [Indexed: 11/24/2022]
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66
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Shahrokhian S, Souri A, Khajehsharifi H. Electrocatalytic oxidation of penicillamine at a carbon paste electrode modified with cobalt salophen. J Electroanal Chem (Lausanne) 2004. [DOI: 10.1016/j.jelechem.2003.09.039] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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67
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Dai J, Chai Y, Yuan R, Zhong X, Liu Y, Tang D. Bis-dimethylaminobenzaldehyde Schiff-Base Cobalt(II) Complex as a Neutral Carrier for a Highly Selective Iodide Electrode. ANAL SCI 2004; 20:1661-5. [PMID: 15636512 DOI: 10.2116/analsci.20.1661] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A new solvent polymeric membrane electrode based on N,N'-bis-(dimethylaminobenzaldehyde)-glycine cobalt(II) [Co(II)-BDMABG] as a neutral carrier is described, which displays a preferential potentiometric response to iodide ion and an anti-Hofmeister selectivity sequence in the following order: I- > ClO4- > Sal- > SCN- > NO2- > Br- > NO3- > Cl- > SO3(2-) > SO4(2-). The electrode exhibits a near-Nernstian potential linear range of 9.0 x 10(-7)-1.0 x 10(-1) M with a detection limit of 6.8 x 10(-7) M and a slope of -53.0 mV/decade in pH 2.0 of a phosphate buffer solution at 20 degrees C. The response mechanism is discussed in view of the A.C. impedance technique and the UV spectroscopy technique. The electrode was successfully applied to the determination of iodide in Jialing River and Spring in Jinyun Mountains with satisfactory results.
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Affiliation(s)
- Jianyuan Dai
- Chongqing Key Laboratory of Analytical Chemistry, Southwest China Normal University, Chongqing 400715, PR China
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68
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All-solid-state potentiometric sensors for ascorbic acid by using a screen-printed compatible solid contact. Anal Chim Acta 2004. [DOI: 10.1016/j.aca.2003.09.060] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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69
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Iodide Selective Electrodes Based on Bis(2-mercaptobenzothiazolato) Mercury(II) and Bis(4-chlorothiophenolato) Mercury(II) Carriers. SENSORS 2003. [DOI: 10.3390/s31100509] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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70
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Amini M, Rafi A, Ghaedi M, Habibi M, Zohory M. Bis(2-mercaptobenzoxazolato)mercury(II) and bis(2-pyridinethiolato)mercury(II) complexes as carriers for thiocyanate selective electrodes. Microchem J 2003. [DOI: 10.1016/s0026-265x(03)00091-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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71
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Asghari A, Amini MK, Mansour HR, Salavati-Niasari M, Rajabi M. Nitrate-selective membrane electrode based on bis(2-hydroxyanil)acetylacetone lead(II) neutral carrier. ANAL SCI 2003; 19:1121-5. [PMID: 12945663 DOI: 10.2116/analsci.19.1121] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A nitrate-selective electrode based on a recently synthesized bis(2-hydroxyanil)acetylacetone lead(II) complex [(haacac)Pb] has been developed. Among different compositions studied, a membrane containing 30.7% poly(vinyl chloride) (PVC), 61.3% dibutyl phthalate (DBP) as a plasticizer, 3% methyltrioctylammonium chloride (MTOAC) as a cationic additive and 5% ionophore (all w/w) exhibited the best potentiometric response toward nitrate ion in aqueous solutions. The potentiometric response of the electrode was linear with a Nernstian slope of -58.8 mV decade(-1) within the NO3- concentration range of 2 x 10(-5)-1 x 10(-1) mol dm(-3). The response time of the electrode was < or =10 s over the entire linear concentration range of the calibration plot. The electrode is suitable for use within the pH range of 5.3-11. The selectivity coefficients for the proposed electrode were improved for some interferences, when compared with those of commercially available nitrate-selective electrodes.
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Affiliation(s)
- Alireza Asghari
- College of Chemistry, Isfahan University of Technology, Isfahan, Iran
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72
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Johnson RD, Bachas LG. Ionophore-based ion-selective potentiometric and optical sensors. Anal Bioanal Chem 2003; 376:328-41. [PMID: 12734632 DOI: 10.1007/s00216-003-1931-0] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2002] [Revised: 03/15/2003] [Accepted: 03/20/2003] [Indexed: 10/20/2022]
Abstract
This paper describes ion-selective electrodes (ISEs) and optodes with a focus on the fundamental mechanisms, response characteristics, and recognition elements (ionophores) described to date for these sensors. The topics covered review the most frequently encountered ideas about ionophore-based sensors, including the theoretical and experimental parameters that influence response, typical ionophore structures, useful membrane compositions, and applications. Since these sensors are applicable in a number of fields, such as clinical, environmental, and process monitoring, as well as more novel approaches such as microfluidic-based systems and micro/nanoprobes, this article provides descriptions that are oriented toward a more general audience. Furthermore, a large portion of this review describes the ionophore component itself in hopes of inspiring ideas in readers of how novel molecular architectures with new ionic targets or improved selectivity can be developed.
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Affiliation(s)
- R Daniel Johnson
- Department of Chemistry, University of Kentucky, Lexington 40505-0055, USA
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73
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Coated wire ion-selective electrode for palladium(II) and its application to catalyst analysis. Anal Chim Acta 2003. [DOI: 10.1016/s0003-2670(03)00058-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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74
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Chai Y, Jiang F, Yuan R, Xu L, Xu W. A Highly Selective Salicylate Electrode Based on Schiff Base Complexes of Cobalt(III). ANAL LETT 2003. [DOI: 10.1081/al-120024329] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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75
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Shamsipur M, Avanes A, Javanbakht M, Ganjali MR, Sharghi H. A 9,10-anthraquinone derivative having two propenyl arms as a neutral ionophore for highly selective and sensitive membrane sensors for copper(II) ion. ANAL SCI 2002; 18:875-9. [PMID: 12200832 DOI: 10.2116/analsci.18.875] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
New polymeric membrane (PME) and coated graphite (CGE) copper(II)-selective electrodes based on 1-hydroxy-2-(prop-2'-enyl)-4-(prop-2'-enyloxy)-9,10-anthraquinone were prepared. The electrodes reveal linear emf-pCu2+ responses over wide concentration ranges (1.0 x 10(-5)-1.0 x 10(-1) M with a slope of 27.3 mV decade-1 for PME and 8.0 x 10(-8)-5.0 x 10(-2) M with a slope of 29.1 mV decade-1 for CGE) and very low limits of detection (8.0 x 10(-6) M for PME and 5.0 x 10(-8) M for CGE). The potentiometric response is independent of the pH of the test solution in the pH range 3.0-6.0. The proposed electrodes possess very good selectivities over a wide variety of other cations, including alkali, alkaline earth, transition and heavy metal ions, the selectivity coefficients for the CGE being much improved over those for the PME. The electrodes were used as indicator electrodes in the potentiometric titration of Cu2+ and in the recovery of copper ions from wastewater.
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76
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Shahrokhian S, Hamzehloei A, Bagherzadeh M. Chromium(III) porphyrin as a selective ionophore in a salicylate-selective membrane electrode. Anal Chem 2002; 74:3312-20. [PMID: 12139034 DOI: 10.1021/ac020099n] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The construction, potentiometric response properties, and applications of a novel ion-selective electrode with high selectivity toward salicylate are described. Chromium(III) tetraphenylporphyrin chloride was used as ion carrier into plasticized PVC membrane. This ionophore is capable of serving as both a positively charged and neutral carrier, depending on the pH of the sample solution. The influence of several variables was investigated to optimize the potentiometric response and selectivity of the electrode. The resulting electrode demonstrates a near-Nernstian response over a wide range of salicylate concentration (10(-6)-10(-1) M). This electrode has a fast response time and micromolar detection limit and could be used over a wide pH range (3-9). The proposed electrode showed very high selectivity for salicylate over a number of common inorganic and organic anions. The specific interaction of salicylate with the central metal of porphyrin is described based on UV-visible absorption spectra. The electrode was successfully applied to the determination of salicylate in pharmaceutical preparations and clinical samples.
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77
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Shamsipur M, Javanbakht M, Lippolis V, Garau A, Filippo GD, Ganjali MR, Yari A. Novel Ag+ ion-selective electrodes based on two new mixed azathioether crowns containing a 1,10-phenanthroline sub-unit. Anal Chim Acta 2002. [DOI: 10.1016/s0003-2670(02)00374-4] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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78
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Malinowska E, Niedziółka J, Roźniecka E, Meyerhoff ME. Salicylate-selective membrane electrodes based on Sn(IV)- and OMo(V)-porphyrins: differences in response mechanism and analytical performance. J Electroanal Chem (Lausanne) 2001. [DOI: 10.1016/s0022-0728(01)00615-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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79
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Shamsipur M, Yousefi M, Hosseini M, Ganjali MR, Sharghi H, Naeimi H. A Schiff base complex of Zn(II) as a neutral carrier for highly selective PVC membrane sensors for the sulfate ion. Anal Chem 2001; 73:2869-74. [PMID: 11467529 DOI: 10.1021/ac001449d] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Novel polymeric membrane (PME) and coated graphite (CGE) sulfate-selective electrodes based on a recently synthesized Schiff base complex of Zn(II) were prepared. The electrodes reveal a Nernstian behavior over wide SO4(2-) ion concentration ranges (5.0 x 10(-5)-1.0 x 10(-1) M for PME and 1.0 x 10(-7)-1.0 x 10(-1) M for CGE) and very low detection limits (2.8 x 10(-5) M for PME and 8.5 x 10(-8) M for CGE). The potentiometric response is independent of the pH of the solution in the pH range 3.0-7.0. The electrodes manifest advantages of low resistance, very fast response, and, most importantly, good selectivities relative to a wide variety of other anions. In fact, the selectivity behavior of the proposed SO4(2) ion-selective electrodes shows a great improvement compared to the previously reported electrodes for sulfate ion. The electrodes can be used for at least 3 months without any appreciable divergence in potentials. The electrodes were used as an indicator electrode in the potentiometric titration of sulfate and barium ions and in the determination of iron in ferrous sulfate tablets.
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Affiliation(s)
- M Shamsipur
- Department of Chemistry, Razi University, Kermanshah, Iran
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80
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Zaugg S, Zhang X, Sweedler J, Thormann W. Determination of salicylate, gentisic acid and salicyluric acid in human urine by capillary electrophoresis with laser-induced fluorescence detection. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 2001; 752:17-31. [PMID: 11254191 DOI: 10.1016/s0378-4347(00)00507-7] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Acetylsalicylic acid (Aspirin) is rapidly metabolized to salicylic acid (salicylate) and other compounds, including gentisic acid and salicyluric acid. Monitoring of salicylate and its metabolites is of toxicological, pharmacological and biomedical interest. Three capillary electrophoresis (CE) methods featuring alkaline aqueous buffers, laser-induced fluorescence (LIF) detection and no solute extraction or derivatization have been explored. A competitive binding, electrokinetic capillary-based immunoassay is developed that recognizes the presence of salicylate and gentisic acid in urine. Differentiation of the two compounds, however, is problematic. With appropriate ultraviolet excitation, many salicylate-related compounds are fluorescent so that CE with direct urine injection and LIF detection permits the determination of salicylate, gentisic acid and salicyluric acid. Using a HeCd laser with 325 nm produces interference-free monitoring of all three compounds. Using 257 nm excitation from a frequency doubled Ar ion laser, native fluorescence of an endogenous urinary compound that co-migrates with gentisic acid is observed. With wavelength-resolved fluorescence detection, however, the two substances are distinguished. Furthermore, this technique, with comparison to literature data, permits the putative assignment of several peaks to other salicylate metabolites, namely glucuronide conjugates of salicylate and salicyluric acid. All three CE-LIF techniques have been applied to toxicological patient urines and urines collected after ingestion of 500 mg acetylsalicylic acid. CE results compare favorably with those obtained by a commercial fluorescence polarization immunoassay and by a conventional photometric assay.
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Affiliation(s)
- S Zaugg
- Department of Clinical Pharmacology, University of Bern, Switzerland
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81
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Amini MK, Shahrokhian S, Tangestaninejad S, Mirkhani V. Iron(II) phthalocyanine-modified carbon-paste electrode for potentiometric detection of ascorbic acid. Anal Biochem 2001; 290:277-82. [PMID: 11237330 DOI: 10.1006/abio.2000.4929] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A chemically modified electrode constructed by incorporating iron(II) phthalocyanine [Fe(II)Pc] into carbon-paste matrix was used as a sensitive potentiometric sensor for detection of ascorbic acid. The resulting electrode exhibits catalytic properties for the electrooxidation of ascorbic acid, and lowers the overpotential for the oxidation of this compound. The faster rate of electron transfer results in a near-Nernstian behavior of the modified electrode, and makes it a suitable potentiometric sensor for detection of ascorbic acid. A linear response in concentration range from 10(-6) to 10(-2) M (0.18--1800 microg ml(-1)) was obtained with a detection limit of 5 x 10(-7) M for the potentiometric detection of ascorbic acid. The modified electrode was used for the determination of ascorbic acid in vitamin preparations. The recovery was 97.2--102.4% for the vitamin added to the preparations with a relative standard deviation of less than 5%. The modified electrode exhibited a fast response time (<10 s),had good stability, and had an extended lifetime.
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Affiliation(s)
- M K Amini
- Chemistry Department, University of Isfahan, Isfahan 81744, Iran
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