Sample records for ion-selective electrodes

Sample records 1 - 6 shown.


Recentes avanços e novas perspectivas dos eletrodos íon-seletivos/ Recent advances and new perspectives of ion-selective electrodes

Torres, Karin Yanet Chumbimuni; Marzal, Percy Calvo; Kubota, Lauro Tatsuo; Bakker, Eric

Resumo em inglês This paper describes the recent progress in the development of polymeric membranes for ion-selective electrodes. The importance of knowing the mechanism of potential development in membranes for ion-selective electrodes to reach lower detection limits and improve selectivity are discussed. Recent advances and future trends of research on ion-selective electrodes are also reported.

Scientific Electronic Library Online (Portuguese)


Construção artesanal de um eletrodo íon seletivo a chumbo(II): uma alternativa para disciplinas experimentais/ Homemade construction of a lead(II) ion selective electrode: an alternative to experimental subjects

Silva, Jonatas Gomes da; Lehmkuhl, Arilson; Alcanfor, Silvia Keli de Barros

Resumo em inglês This works proposes a homemade construction of a lead(II) ISE of solid membrane (Ag2S/PbS) to determine Pb2+ ions in potentiometric titrations, using damaged combined glass electrodes. This electrode can be constructed in teaching laboratories, using it as a learning tool related to the theoretical principle of ISE. The analytical curve obtained (y = 27.056x + 337.58; R = 0.996) was linear on the range of 1 x 10-5 to 1 mol L-1 and has presented a very close behavior of th (mais) e Nernstian. The homemade ISE has presented a similar selectivity to the commercial electrodes, showing to be a good alternative to the experimental activities on teaching laboratories.

Scientific Electronic Library Online (Portuguese)


Utilização de eletrodos potenciométricos de amálgama em estudos de complexação de substâncias húmicas/ The use of potentiometric amalgam electrodes for complexation studies of humic substances

Abate, Gilberto; Masini, Jorge C.

Resumo em inglês Potentiometric amalgam electrodes of lead, cadmium, and zinc are proposed to study the complexation properties of commercial and river sediment humic acids. The copper complexation properties of both humic acids were studied in parallel using the solid membrane copper ion-selective electrode (Cu-ISE). The complexing capacity and the averaged conditional stability constants were determined at pH 6.00 ± 0.05 in medium of 2x10-2 mol L-1 sodium nitrate, using the Scatchard m (mais) ethod. The lead and cadmium amalgam electrodes presented a Nernstian behavior from 1x10-5 to 1x10-3 moles L-1 of total metal concentration, permitting to perform the complexation studies using humic acid concentrations around of 20 to 30 mg L-1, that avoids colloidal aggregation. The zinc amalgam electrode showed a subnernstian linear response in the same range of metal concentrations. The Scatchard graphs for both humic acids suggested two classes of binding sites for lead and copper and one class of binding site for zinc and cadmium.

Scientific Electronic Library Online (Portuguese)


Uma célula simples para adaptação de eletrodos seletivos comerciais em sistemas de análises em fluxo/ A simple cell for assembling commercial ion-selective electrodes in continuous flow analyzers

Marin, Maria Angélica Bonadiman; Ganzarolli, Edgard Moreira; Queiróz, Roldão Rooseveld Urzêdo de; Souza, Ivan Gonçalves de

Resumo em inglês A simple flow cell for potentiometric detection is described. It was assembled by making use of two perspex pieces fixed together by means of four screws, and allow the connection of plane membrane conventional electrodes to flow system. Details about its construction are presented. The device performance was evaluated by making use of a cyanide ion-selective electrode. The relative standard deviation was about 0.5% with a detection limit of 8.0 x 10-6 mol CN- dm-3. Under experimental conditions, the linear range was 10-5 to10-2 mol dm-3.

Scientific Electronic Library Online (Portuguese)


Transdutores potenciométricos a base de polímeros condutores: aplicações analíticas/ Potentiometric transducers based in conducting polymers: analytical applications

Rover Júnior, Laércio; Oliveira Neto, Graciliano de; Kubota, Lauro Tatsuo

Resumo em inglês A review is given about the most relevant advances on the analytical applications of conducting polymers in potentiometric sensors. These organic polymers represent a new class of materials with conducting properties due to its doping by ions. Several polymers already were synthesized such as polypyrrole, polyaniline, polythiophene, among others. Particular attention is devoted to the main advantages supplied by ion selective electrodes and gas sensors using conducting po (mais) lymers, as well as the incorporation of bioactive elements in these polymers for the construction of biosensors. The correlation between structure, stability and ability to ion exchange of some conducting polymers applied as potentiometric transducers, is discussed.

Scientific Electronic Library Online (Portuguese)


Estudo da capacidade de complexação e sua relação com algumas variáveis ambientais em cinco represas do Rio Tietê/Brasil/ Study of complexation capacity and its relationship with some environmental variables in five reservoirs of the Tietê River system

Borges, Elisangela C. L.; Mozeto, Antonio Aparecido; Neves, Eduardo F. Almeida; Borges Neto, Waldomiro; Bezerra, José Mauro

Resumo em inglês The copper and cadmium complexation properties in natural sediment suspensions of reservoirs of the Tietê River were studied using the solid membrane copper and cadmium ion-selective electrodes. The complexation and the average conditional stability constants were determined under equilibrium conditions at pH=6.00 ± 0.05 in a medium of 1.0 mol L-1 sodium nitrate, using the Scatchard method. The copper and cadmium electrodes presented Nernstian behavior from 1x10-6 (mais) to 1x10-3 mol L-1 of total metal concentration. Scatchard graphs suggest two classes of binding sites for both metals. A multivariate study was done to correlate the reservoirs and the variables: complexation properties, size, total organic carbon, volatile acid sulfide, E II and pH.

Scientific Electronic Library Online (Portuguese)