茜素S选择电极的研制和应用

本文报道了茜素S电极的研制和应用。比较了季铵盐、季鏻盐、碱性染料和邻二氮菲金属配合盐作为活性物质、各种介体溶剂以及活性物质在膜相中的含量对电极性能的影响。以三辛基甲基氯化铵制成的PVC膜型电极对茜素S在2×10~(-4)～5×10~(-7)M浓度范围内呈Nernstian响应,检测下限为2×10~(-7)M。测定了一些阴离子的选择系数,ClO_4~-,CNS~-,I~-以及能与茜素S配合的金属离子有明显干扰。报道了以茜素S电极为指示电极,用EDTA和茜素S为滴定剂滴定钪和稀土的情况。以茜素8电位滴定钪及钴-钐合金中的钐,都获得良好的结果。     

A new selenite selective membrane electrode and its application

A new membrane ion selective electrode sensitive to selenite ion has been developed. The electrode consisted of 1,2-phenylenediamine selen complex PIS (piaselenol) as the active material, PVC or SR (silicon rubber) as membrane matrix and DBF (dibutylphtalate) as plasticizer. This electrode showed linear response for selenite ion in the 10(-5)-10(-1)M concentration range. The slope of the linear portion was 21 mV/10-fold change in selenite concentration. The effect of membrane composition and membrane thickness on electrode response was studied and the electrode which contains 2% PIS, 49% PVC and 49% DBF was found to be the most sensitive one to selenite. The slope of the electrode did not change for 2 months and the pH change did not affect the response of the electrode in pH range of 3-9. The interferences of SO(4)(2-), SO(3)(2-), S(2-), HPO4(2-), CI(-), Br(-), and I(-) are investigated and while no interference was observed for SO(4)(2-), SO(3)(2-), S(2-) and I(-), a very small interference was observed for CI(-) and Br(-). The selenium present in anodic slime is determined using this electrode.     

Preparation of a new solid state fluoride ion selective electrode and application

A new solid state fluoride ion selective electrode composed of 70% Ag₂S, 10% Cu₂S and 20% CaF₂ has been developed. An analytically useful potential change occurred, from 1 × 10⁻⁶ to 1 × 10⁻¹ M fluoride ion. The slope of the linear portion (1 × 10⁻¹-1 × 10⁻⁵ M) was about 26 ± 2 mV/10-fold concentration changes in fluoride. It was found that pH change between 1 and 8 had no effect on the potential of the electrode. There was no interference of most common cations such as K^+, Na⁺, Ca²⁺ and Mg²⁺ and anions such as Cl⁻, NO₃⁻, SO₄²⁻ and PO₄³⁻. The lifetime of the electrode was more than 2 years, when used at least 4-5 times a day, and the response time was about 60 s.The measurements were made at constant ionic strength (0.1 M NaNO₃) and at room temperature. This electrode has been used for the determination of fluoride ion in Ankara city tap water and in bottled spring water using standard addition method. The validation of the electrode has been made with a commercial fluoride ion selective electrode (Orion) and high consistency was obtained.     

Preparation and application of a new glucose sensor based on iodide ion selective electrode

An electrode for glucose has been prepared by using an iodide selective electrode with the glucose oxidase enzyme. The iodide selective electrode used was prepared from 10% TDMAI and PVC according our previous study. The enzyme was immobilized on the iodide electrode by holding it at pH 7 phosphate buffer for 10 min at room temperature. The H₂O₂ formed from the reaction of glucose was determined from the decrease of iodide concentration that was present in the reaction cell. The iodide concentration was followed from the change of potential of iodide selective electrode. The potential change was linear in the 4×10⁻⁴ to 4×10⁻³ M glucose concentration (75-650 mg glucose/100ml blood) range. The slope of the linear portion was about 79 mV per decade change in glucose concentration. Glucose contents of some blood samples were determined with the new electrode and consistency was obtained with a colorimetric method. The effects of pH, iodide concentration, the amount of enzyme immobilized and the operating temperature were studied. No interference of ascorbic acid, uric acid, iron(III) and Cu(II) was observed. Since the iodide electrode used was not an AgI-Ag₂S electrode, there was no interference of common ions such as chloride present in biological fluids. The slope of the electrode did not change for about 65 days when used 3 times a day.     

Preparation and properties of solid state selenite ion selective electrodes and their applications

A new selenite ion selective electrode using solid salts of Ag(2)Se and Cu(2)S has been developed. Detailed information is provided concerning the composition, working pH and conditioning of the electrode. The change of potential with concentration is found to be linear in the range of 10(-5)-10(-2) M, the slope of the linear portion is 28 mV/10-fold change in selenite concentration. The effect of other ions on selenite response is evaluated and selenium content of anodic slime is determined.     

Preparation and properties of a new solid state borate ion selective electrode and its application

A new borate ion selective electrode using solid salts of Ag₃BO₃, Ag₂S and Cu₂S has been developed. Detailed information is provided concerning the composition, working pH and conditioning of the electrode. An analytically useful potential change occurred from 1 × 10⁻⁶ to 1 × 10⁻¹ M borate ion. The slope of the linear portion was 31 ± 2 mV/10-fold changes in borate concentration. The measurements were made at constant ionic strength (0.1 M NaNO₃) and at room temperature. The effect of Cl⁻, Br⁻, NO₃⁻, SO⁼₄, H₂PO₄⁻ anions and K⁺, Na⁺, Cu²⁺, Ag⁺, Ca²⁺ cations on borate response is evaluated and it was found that only Ag⁺ had a small interference effect. The lifetime of the electrode was more than two years, when used at least 4-5 times a day, and the response time was about 20-30 s. Borate content in waste water of borax factory, tap water of a town situated near to the borax factory and city tap water far from these mines were also determined. The validation was made with differential pulse polarography for the same water sample, and high consistency was obtained.     

Calcium ion selective membrane electrode

The calcium salts of the mono- and diesters of [4-(1,1,3,3-tetramethylbutyl)phenyl phosphoric acid] have been prepared, and the individual esters as well as mixtures of the esters have been used with several varieties of polyvinyl chloride to construct macro membrane electrodes selective to calcium ions. These electrodes have been calibrated by using solutions of CaCl₂ and Ca ion buffers. The mixed ester electrodes showed Nernstian response in the concentration range 10^-1 to 10^-7M; the diester electrodes showed Nernstian response down to 7.9 x 10^-8M. The detection limit of the mixed ester electrode was 10^-8M, whereas that of the diester electrode was 7.9 x 10^-9M. Contrary to these results, the monoester electrodes showed unsatisfactory behavior. The responses of both the mixed ester and diester electrodes to calcium ions were not affected by the presence of sodium, potassium, or other divalent ions. Only ferric and lanthanum ions showed interferences with the electrode response to calcium ions. p]The electrode response was independent of pH in the approximate range 5–8 at a CaCl₂ concentration of 10^-4M. As the Ca ion concentration was increased, the range of pH independence widened to approximately 4–8. The dynamic response time constant of the mixed ester electrode was in the range 0.7–1.5 sec, whereas that of the diester electrode was in the range 0.5–0.75 sec.     

盐酸依匹斯汀PVC膜电极的研制及应用

以四苯硼酸钠与盐酸依匹斯汀生成的离子缔合物为电活性物质,研制了盐酸依匹斯汀PVC膜选择性电极。在pH 5的HCl-NaOH溶液中,电极的线性范围为6.3×10-7~1.0×10-1mol/L,斜率为49 mV/pC(10℃),检出限为1.89×10-7mol/L。应用此电极测定药物中盐酸依匹斯汀含量,RSD3%,回收率为97.5%~100.2%。     

氧氟沙星选择性电极的改进研究及应用

分别以氧氟沙星-磷钼酸与氧氟沙星-四苯硼钠离子缔合物作为电活性物质制备氧氟沙星选择性电极,并系统研究和比较了这两种电极的响应性能。实验表明以磷钼酸-氧氟沙星离子对作为电活性物质,以四苯硼钠作添加剂所制备的氧氟沙星电极呈现了良好的Nernst响应,且其选择性明显提高。用该电极测定了药物中的氧氟沙星。     

涂碳型PVC膜培氟沙星选择电极的研制

报道一种以盐酸培氟沙星与溴汞酸盐生成的分子缔合物为电活性物质的新型涂碳PVC膜培氟沙星选择电极。在pH 1 .5～ 4.5范围内 ,电极对培氟沙星的Nernst响应范围为 1 .0× 1 0 - 2 ～ 5 .0× 1 0 - 5mol/L ,检测限为 4.2× 1 0 - 6mol/L。方法的平均回收率为 98.5 % ,RSD为 1 .0 %     

涂丝型PVC膜盐酸莱克多巴胺选择电极的研制与应用

本文报道了以盐酸莱克多巴胺与四苯硼钠形成的缔合物为电活性物的新型聚氯乙烯(PVC)膜盐酸莱克多巴胺涂丝选择电极,电极的线性响应范围为1.0×10-6～1.0×10-2 mol/L,极差电位为46mV/pC,检测下限为7.9×10-7mol/L.该电极响应迅速,重现性好,用此电极以标准曲线法对猪尿样中盐酸莱克多巴胺进行了测定,结果与高效液相色谱法相符.     

Novel PVC membrane-based thoron ion selective electrode and its application: determination of zirconium

The construction, electrochemical evaluation and application of new electrode selective to the thoron reagent are reported. The electrode incorporates bathophenanthroline iron: thoron ion pair as electroactive sensing material, o-nitrophenyl octyl ether as plasticizer and PVC as support matrix, exhibits a Nernstian response to thoron with a slope of -29.7+/-1 mV per decade in a range of concentration from 1.0x10(-6) to 5.0x10(-2) mol L(-1), a detection limit of 6.0x10(-7) mol L(-1) and fast response time of less than 30 s. The proposed electrode is successfully applied to zirconium ion determination in aqueous samples using indirect potentiometry and the results obtained are compared with those provided by spectrophotometric analysis using thoron as complexing agent.     

涂丝型盐酸地尔硫卓选择电极的研制与应用

研制了一种以盐酸地尔硫卓与碘汞酸盐缔合物为电活性物的涂丝型盐酸地尔硫卓选择电极,电极的线性响应范围1.0×10-3~1.0×10-5mol.L-1,级差电位为28 mV/pc,检测限为4.5×10-5mo.lL-1.该电极响应迅速,重现性好,用此电极以标准曲线法测定了盐酸地尔硫卓片剂的含量,结果与药典法相符.     

Creatinine biosensor based on ammonium ion selective electrode and its application in flow-injection analysis

A new, highly sensitive, fast responding and stable potentiometric biosensor for creatinine determination is developed. The biosensor is based on an ammonium ion-selective electrode. Creatinine deiminase (EC 3.5.4.21) is chemically immobilized on the surface of the polymeric ion-sensitive membrane in the form of monomolecular layer using a simple, one-step carbodiimide covalent attachment method. The resulting enzyme electrodes are useful for measurement under flow injection analysis (FIA) conditions. The biosensors exhibit excellent operational and storage stability. The enzyme electrodes retain over 70% of initial sensitivity after ten weeks of work under FIA conditions. The storage stability at 4 °C is longer than half a year without loss of sensitivity. Under optimized conditions near 30 samples per hour can be analyzed and the determination range (0.02-20.0 mmol l⁻¹) fully covers creatinine concentrations important from clinical and biomedical point of view. The simple biosensor/FIA system has been successfully used for determination of creatinine in urine, serum and posthemodialysate samples.     

Liquid-membrane type 8-quinolinol-5-sulfonate ion selective electrode and its application to potentiometric titration

A nitrobenzene extract of the ion-pair consisting of 8-quinolinol-5-sulfonate (Hqs^?) and the cation of zephiramine (Z⁺Cl^?, benzyldimethyltetradecylammonium chloride) was used as an ion-exchanging liquid membrane for the electrode responding to Hqs^? ion. The potential response showed the Nernstian slope with the Hqs^? activities varying from 10^?2 to 10^?4.5 mol l^?1. The break points in the potential-pH plot with the constant analytical concentration of H₂qs correspond to the values of the negative logarithm of the acid dissociation constant of H₂qs. The present electrode was successfully applied to the potentiometric titration of copper(II) with H₂qs.     

Conducting polymer ion sensor electrodes-III. Potentiometric sulfide ion selective electrode

A new potentiometric sensor electrode for sulfide based on conducting polymer films is introduced. The electrode is formed by electrochemically depositing a film of poly(3-methylthiophene) and poly(dibenzo-18-crown-6) onto an alloy substrate. Different methods were used for the electrode preparations. The alloy used has a low melting point, which allowed its use for manufacturing a microsize version of this electrode. The electrode response is stable for 3 days. The working temperature range for this electrode is between 10 and 40 degrees C. The linear dynamic range is 1.0x10(-7)-1.0x10(-2) M and measures total sulfide concentration over a range of pH from 1 to 13. The polymer electrode showed high selectivity for sulfide in the presence of many common interfering anions. The electrode is useful for the measurement of total sulfide in biological environments and can be manufactured in the micron scale. Therefore, it will be useful for the measurement within biofilms.     

The role of PVC in ion selective electrode membranes

The behaviour of a solution of NaBPh₄ in a PVC membrane plasticized by di-octyl sebacate is compared with a solution of NaBPh₄ in pure liquid di-octyl sebacate. In the liquid the NaBPh₄ is present as ion pairs with ~ 0.2% of these dissociated in a 1 mM solution. By contrast in the membrane 1 mM solution is 74% dissociated. This difference in behaviour arises chiefly from the higher dielectric constant of the membrane phase.     

Preparation of polyaniline modified electrode in novel ionic liquid and its application in ion chromatography

In this work, a promising electrochemical detector has been fabricated by immersing a glass carbon electrode (GCE) in aniline containing novel ionic liquid and scanning between -1.0 and 1.0 V for 40 cycles, and was used in ion chromatography (IC) system. The morphology of the modified electrode surface was characterized by scanning electron microscope (SEM). The polyaniline (PANI) film showed excellent electrocatalytic activity than bare GCE and provided enhanced selectivity and stability for the detection of ascorbic acid (AA). Separated by IC with phosphate buffer solution (pH = 5.2) as eluent, AA could be determined by the PANI/GCE successfully at the working potential of 0.3 V. The retention time of AA was approximately 5.75 min, and the peak shape of AA was satisfactory. The calibration curve of AA was linear (r > 0.99), in the range between 0.05 mg/L and 1000 mg/L and the detection limit was 23.41 μg/L (S/N = 3). The proposed method was successfully applied in the detection of AA in four beverage samples. The recoveries of AA in these samples were from 92.32% to 110.57%.     

New metal complex systems as electrode active components of ion selective electrode membranes

New donor-acceptor 3d-transition metal complexes were synthesized and the cobalt and nickel complexes were studied by X-ray diffraction; CIF files CCDC no. 1516693 (III(Ni)) and 1516694 (III(Co)). The crystal structure details of the reactants were discussed. The proposed compounds were tested as the active components of ion selective electrode membranes for determination of thiocyanate ions. The selectivity of the SCN-SE with metal complex-based membranes depends on the ligand structure and the central metal ion type. The proposed electrode is suitable for determination of thiocyanate ions in the presence of sulfate, chloride, nitrate, nitrite, bromide, and iodide ions.     

Coated wire thorium ion selective electrode: Part I

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.