A Selective Membrane Electrode for Thiocyanate Ion Based on a Copper-1,8-Dimethyl-1,3,6,8,10,13-Azacyclotetradecane Complex as Ionophore

Poursaberi, Tahereh; Salavati-Niassari, Masoud; Khodabakhsh, Saaghar; Hajiaghababaei, Leila; Shamsipur, Mojtaba; Yousefi, Mohammad; Rouhani, Shohre

doi:10.1081/al-100108409

Cited by 29 publications

(15 citation statements)

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“…It is well understood that, the sensitivity and selectivity of the ion-selective electrodes depend not only on the nature of the ion-carrier used, but also significantly on the membrane composition and the properties of solvent mediators and additives used. [9][10][11][12][13][14] Thus, the influences of the membrane composition, nature of solvent mediator and additive on the response characteristics of the I − sensor were investigated, and the results are shown in Table 1 and Figure 3. As it is seen, among three different plasticizers used, the use of DBP resulted in the best response characteristics (no.…”

Section: Resultsmentioning

confidence: 99%

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Titanium Acetylacetonate as an Excellent Ion-Carrier in Construction of Iodide Sensor

2003

Bulletin of the Korean Chemical Society

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Titanium acetylacetonate was used in the construction of a PVC-based membrane electrode. This sensor shows very good selectivity for iodide ion over a wide variety of common inorganic and organic anions. It exhibits Nernstian behavior with a slope of 59.1 mV per decade. The working concentration ranges of the sensor are 1.0 × 10 −1 -5.0 × 10 −6 M with a detection limit of 3.0 × 10 −6 M. The response time of the sensor is very fast (<8 s), and can be used for at least twelve weeks in the pH range of 4.0-9.2. The best performance was obtained with a membrane composition of 30% PVC, 65% dibutylphthalate, 3% titanium acetylacetonate and 2% hexadecyltrimethylammonium bromide. The proposed sensor was successfully applied as an indicator electrode for titration of iodide with silver ion.

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Section: Resultsmentioning

confidence: 99%

“…It is well known that the cationic additives improve the EMF response of the anion selective electrodes. [11][12][13][14][15] As it is obvious from Table 1, the presence of HTAB in the membrane composition (no. 4-9) increases the sensitivity of the sensors.…”

Section: Resultsmentioning

confidence: 99%

Titanium Acetylacetonate as an Excellent Ion-Carrier in Construction of Iodide Sensor

2003

Bulletin of the Korean Chemical Society

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“…22 The data given in Table 1 reveal that the presence of an additive has a beneficial influence on the performance characteristics of the membrane electrode. The addition of 5% HTAB acid as a suitable additive 16,17,20 will increase the slope of the potential response of the sensor from a poor value of -15. The presence of cationic additives, such as hexadecyltrimethylammonium bromide (HTAB), can reduce the ohmic resistance 23 and improve the response behavior and selectivity of the membrane electrodes.…”

Section: Resultsmentioning

confidence: 99%

“…16,20 Besides the critical role of the nature of the ion-carrier in preparing membrane-selective sensors, some other important features of the PVC membrane, such as the amount of ionophore, the nature of the solvent mediator, the plasticizer/PVC ratio, and especially the nature of the additives used, are known to significantly influence the sensitivity and selectivity of ion-selective electrodes. [16][17][18]20 Thus, different aspects of preparing of the membrane based on the ZPC for SO4 2-ions were optimized; the results are summarized in Table 1. As is obvious from Table 1, benzyl acetate is a more effective solvent mediator than dibutyl phthalate in preparing a SO4 2-ion-selective electrode.…”

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confidence: 99%

Novel Membrane Potentiometric Sulfate Ion Sensor Based on Zinc-Phthalocyanine for the Quick Determination of Trace Amounts of Sulfate

et al. 2003

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Investigations about ion-selective electrodes are steadily increasing. The rapid development of these electrodes reflects the extent to which these devices meet the needs for accurate, inexpensive, and rapid analytical and control techniques. These electrodes are being used in clinical analysis, and in routine control analysis of some cations and anions. 1 It has been well documented that the selective complexation of anions by synthetic ionophores can be used to design anion-selective electrodes that exhibit a non-Hofmeister selectivity pattern, i.e., selectivities that are not based solely on the analyte lipophilicity.2 Most of these electrodes were based on vitamin B12 derivatives, 3 [16][17][18] we reported on three selective sulfate sensors based on a new zinc Schiff base complex, a derivative of tetraaza-bicyclo heptane and a pyrilium compound. In this work, we introduce a highly selective and sensitive membrane electrode for the quick determination sulfate ions based on a highly lipophilic zinc phthalocyanine complex as an excellent ionophore. Experimental Reagents and materialsReagent-grade dibutyl phthalate (DBP), benzyl acetate (BA), hexadecyltrimethylammonium bromide (HTAB), tetrahydrofuran (THF) and high relative molecular weight PVC were purchased from Aldrich Chemical Company and used as received. Potassium salts of all the anions used (all from Merck) were of the highest purity available and used without any further purification, except for vacuum drying over P2O5. Zinc-phthalocyanine (Fig. 1) was synthesized and purified by a new general method, as described elsewhere. 19 Tryiply distilled deionized water was used throughout. Preparation of electrodes and potential measurementsThe general procedure to prepare a PVC membrane was to thoroughly mix 32 mg of powdered PVC, 5 mg of ionophore ZPC, 3 mg of cationic additive HTAB and 60 mg of plasticizer BA. The mixture was the dissolved in 3 ml of dry THF. The resulting clear mixture was slowly evaporated until an oily concentrated mixture was obtained. Poly(vinyl chloride) (PVC) based membranes of zinc-phthalocyanine (ZPC) with hexadecyltrimethylammonium bromide (HTAB) as a cation excluder, and dibutyl phthalate (DBP) and benzyl acetate (BA) as plasticizing solvent mediators were prepared and investigated as a SO4 2-selective electrode. The best performance was observed with a membrane having a composition of ZPC-PVC-HTAB-BA in a ratio of 5%:32%:3%:60%, which works well over a wide concentration range (1.0 × 10 -2 -1.0 × 10 -6 M) with a Nernstian slope of -29.2 mV per decade of activity, between the pH values of 2.0 to 7.0. This sensor shows a very fast response time of 10 s, and can be used over a period of 2 months with good reproducibility. The proposed sensor displays excellent selectivity for SO4 2-over a large number of common inorganic anions. The sensor has been successfully applied for the direct and indirect determination of sulfate and zinc in zinc sulfate tablets, respectively. It was also used as an indicator electrode in the potentiometric...

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“…5,[7][8][9][10][11][12][13] However, most of these SCN -sensors have one, two or, in some cases, all of the following problems: a) high detection limit, b) narrow working concentration range and/or c) serious interfering effect of such anions as ClO4 -, I -and IO4 -.…”

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Determination of SCN– in Urine and Saliva of Smokers and Non-Smokers by SCN–-Selective Polymeric Membrane Containing a Nickel(II)-Azamacrocycle Complex Coated on a Graphite Electrode

et al. 2002

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The conventional anion-selective electrodes based on quaternary ammonium or phosphonium salts always display the so-called Hofmeister selectivity pattern. 1 Since the 1980's, research interest in anti-Hofmeister anion selective membrane electrodes has increased more and more. Recently, electrodes based on derivatives of vitamin B12 and transitional metal complexes of porphyrins, and phthalocyanines have been reported. [2][3][4][5][6] These electrodes demonstrated potentiometric anion selectivity sequences apparently deviating from the Hofmeister sequences. Such deviations result from the unique interaction of the central metals with an anion rather than from the hydration free energy and the relative solubility of the individual anions in the solvent mediator.Due to the vital importance of selective SCN -determination, especially in food, biological and water samples, there are several reports on the preparation of SCN -selective membrane electrodes based on a variety of ion carriers.5,7-13 However, most of these SCN -sensors have one, two or, in some cases, all of the following problems: a) high detection limit, b) narrow working concentration range and/or c) serious interfering effect of such anions as ClO4 -, I -and IO4 -.In this work we report a coated graphite membrane electrode based on Ni(II)-2,2′,4,9,9′,11-hexamethyltetraazacyclotetradecanediene perchlorate (NiL) for potentiometric monitoring of ultra trace amounts of SCN -. Experimental ReagentsReagent grade dibutyl phthalate (DBP), benzyl acetate (BA), acetophenone (AP), hexadecyltrimethylammonium bromide (HTAB), tetrahydrofuran (THF), and high relative molecular weight (PVC) were purchased from Aldrich and used as received. Nickel(II)-2,2′,4,9,9′,11-hexamethyltetraazacyclotetradecanediene perchlorate (NiL) was synthesized and purified as described elsewhere.14 Potassium salts of all anions used (all from Merck) were of the highest purity available; they were used without any further purification except for vacuum drying The construction, performance characteristics, and application of a novel polymeric membrane coated on a graphite electrode with unique selectivity towards SCN -are reported. The electrode was prepared by incorporating Ni(II)-2,2,4,9,9,11-hexamethyltetraazacyclotetradecanediene perchlorate into a plasticized poly(vinyl chloride) membrane. The influences of membrane composition, pH and foreign ions were investigated. The electrode displays a near Nernstian slope (-57.8 mV decade -1 ) over a wide concentration range of 1 × 10 -7 -1 × 10 -1 M of SCN -ion. The electrode has a detection limit of 4.8 × 10 -8 M (2.8 ng/cm 3 ) SCN -and shows response times of about 15 s and 120 s for low to high and high to low concentration sequences, respectively. The proposed sensor shows high selectivity towards SCN -over several common organic and inorganic anions. The electrode revealed a great enhancement in selectivity coefficients and detection limit for SCN -, in comparison with the previously reported electrodes. It was successfully applied to the d...

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A Selective Membrane Electrode for Thiocyanate Ion Based on a Copper-1,8-Dimethyl-1,3,6,8,10,13-Azacyclotetradecane Complex as Ionophore

Cited by 29 publications

References 15 publications

Titanium Acetylacetonate as an Excellent Ion-Carrier in Construction of Iodide Sensor

Titanium Acetylacetonate as an Excellent Ion-Carrier in Construction of Iodide Sensor

Novel Membrane Potentiometric Sulfate Ion Sensor Based on Zinc-Phthalocyanine for the Quick Determination of Trace Amounts of Sulfate

Determination of SCN– in Urine and Saliva of Smokers and Non-Smokers by SCN–-Selective Polymeric Membrane Containing a Nickel(II)-Azamacrocycle Complex Coated on a Graphite Electrode

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