Chemia Analityczna Volume 46, Number 1
(January - February 2001)

Membrane Based on Decyl-18-crown-6 for Potassium Selective Sensor

by Elena Hopartean1, Elena Maria Pica2, Coroian Ana1, Viorica Cosma1, Ioana Hopartean1

1Institute of Chemistry, Fantanele 30, 3400 Cluj-Napoca, Romania
2Technical University of Cluj-Napoca, Muncii 105, 3400 Cluj-Napoca, Romania

Key words:  crown ethers, potassium PVC membrane sensor, potassium potentiometric, determination, ion-selective electrode, ionophores

Four kinds of 18-crown-6 derivatives were studied as ionophores in plasticized poly(vinyl chloride) (PCV) in order to obtain potassium selective membrane. The properties of the sensor were studied in detail. For the optimization of the selectivity toward K+ over Na+ the influence of the following factors was studied: nature and concentration of the ionophore; nature and concentration of the plasticizer and lipophilic salt addition. The potassium ion-selective membrane electrode was designed. The electrode has a fast and Nernstian response in the 1 x 10-1- 2 x 10-5 mol l-1 K+, after six months of continuous measurements. The change of pH in the range 2-10.5 does not affect the response of the electrode. The internal resistance of the electrode was measured. The electrode shows a good stability and can be used in the potentiometric determination.

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