Proposed Membrane Electrode Research Articles

Copper(I)-bathocuproine complex as carrier in iodide-selective electrode

A PVC membrane electrode for iodide ions based on Cu(I)-bathocuproine as ionophore in membrane composition is prepared. The electrode exhibits a linear response over a wide concentration range 5.0×10−6 to 2.0×10−1moll−1 with a detection limit 1.0×10−6moll−1. The proposed membrane electrode shows Nernstian behavior with a slope of −56.8mV/decade, a fast response time 10s and a lifetime at least 3 months. Iodide-selective electrode reveals good selectivities for iodide ion over a wide variety of the other anions and can be used in pH range of 3–9. It can also be used as an indicator electrode in potentiometric titration of iodide ion.

Novel PVC-based copper(II) membrane sensor based on 2-(1'-(4'-(1''-hydroxy-2''-naphthyl)methyleneamino)butyl iminomethyl)-1-naphthol.

A copper(II) ion-selective PVC membrane sensor based on 2-(1'-(4'-(1''-hydroxy-2''-naphthyl)methyleneamino)butyl iminomethyl)-1-naphthol (BHNB) as a novel Schiff base containing a sensing material has been successfully developed. The sensor exhibits a good linear response of 29 mV per decade within the concentration range of 10(-1)-10(-6) M of Cu2+. The sensor shows good selectivity for copper(II) ion in comparison with alkali, alkaline earth, transition and heavy metal ions. The BHNB-based sensor is suitable for use with aqueous solutions of pH 3.5-7.0 and displays minimal interference by Sr(II), Cd(II), Hg(II), Zn(II) and Pb(II), which are known to interfere with other previously suggested electrodes. The proposed membrane electrode was used as a sensor for determining the Cu(II) content in black tea samples. It was also applied as an indicator electrode in the potentiometric titration of Cu2+ ions with EDTA.

Al(III)-Selective Electrode Based on Furil as Neutral Carrier

A PVC membrane electrode for aluminum(III) ions based on Furil (ethan dione, di-(2-furyl)) as neutral carrier was prepared. The electrode exhibits a near Nernstian response for Al3+ ions over a wide concentration range (1.0×10−6 to 1.0×10−2 mol dm−3) with a limit of detection 1.3×10−7 mol dm−3. It has a relatively fast response time and can be used for at least 2 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 in acidic media. It was used as an indicator electrode in potentiometric titration of aluminum ions.

Nickel(II) Ion-Selective Electrode Based on 2,5-Thiophenyl bis(5-tert-Butyl-1,3-Benzoxazole

ABSTRACT A PVC membrane sensor for Nickel (II) ions based on 2,5-thiophenyl bis(5-tert-butyl-1,3-benzoxazole) as membrane carrier was prepared. The sensor exhibits a Nernstian response for Ni2+ ions over a wide concentration range (10−2–10−5M). It has a relatively fast response time and can be used for at least 2 months without any considerable divergence in potentials. The nature of the plasticizer, the additive, the concentration of internal solutions in the electrodes and the composition of the membrane were investigated. The proposed membrane electrode revealed very good selectivities for Ni2+ over a wide variety of other metal cations and could be used in pH range of 4.0–8.0. It was successfully applied for the direct determination of Ni2+ in solution and as an indicator electrode in potentiometric titration of nickel ion in both water and 85% acetonitrile solutions.

Lead Ion-Selective Electrode Based on 4′-Vinylbenzo-15-crown-5 Homopolymer

A PVC membrane electrode for lead ions based on 4′-vinylbenzo-15-crown-5 homopolymer as membrane carrier was prepared. The electrode exhibits a Nernstian response for Pb2+ions over a wide concentration range (4.0 × 10−3to 1.0 × 10−6M), with a limit of detection of 7.0 × 10−7M. It has a response time of 80 s and can be used for at least 4 months without any considerable divergence in potentials. The proposed membrane electrode revealed very good selectivities for Pb2+over a wide variety of other cations and could be used in the pH range 2.0–6.0. It was used as an indicator electrode in potentiometric titration of lead ions in both water and 90% methanol solutions.

Performance characteristics of a Labetalol‐H plus‐tetraphenylborate selective electrode

AbstractThe construction and performance characteristics of an ion selective membrane electrode for labetalol drugs in protonated form, based on their ion‐pair complexes with sodium tetraphenylborate (TPB‐Na+) incorporated in a poly(vinyl chloride) matrix, are described. The Labetalol‐H+ selective electrode can be used practically for the determination of the pharmaceutical compound by direct potentiometry. The potentiometric sensor exhibits near‐Nernstian response from 10−2 M to about 10−5 M, with a slope of 55 mV/decade of concentration and detection limit of 4.46 × 10−6 M. The influence of changing the membrane characteristics, pH, and temperature of the test solution on the electrode potential are studied. The response time varies from a few seconds to several minutes, depending on labetalol concentration. The selectivity of the electrode for Lab‐H+ toward primary, secondary, tertiary, and quaternary amines is investigated. Determination of Lab‐H+ in pharmaceutical tablets is performed using the proposed membrane electrode. No interference from any excipients in the tablets was observed.