Lead(II) and copper(II) ion-selective electrodes based on two heterocyclic compounds
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In this paper, two nitrogen, sulphur or oxygen containing heterocyclic compounds were used as ionophores in ion-selective electrodes. In these two ion-selective electrodes, 2,6-di(5-methyl-1,3,4-oxadiazol-5-yl)pyridine (DMOP) gives the best Pb2+ sensitivity and 2,5-di(2′-methylpyridinethio)thiadiazole (DPTD) gives the best sensitivity for Cu2+. These electrodes are composed of KTpClPB as anion excluder and DOS as plasticizer. The two membrane electrodes show Nernstian or near-Nernstian response towards Pb2+ or Cu2+ (29.3 and 27.3 mV/decade, respectively) over the concentration range 10−5∼10−2 and 10−6∼10−3 M, respectively. The response time was less than 20 sec and a good reproducibility over a period of 2 months was observed. The electrodes exhibited good selectivities over a number of alkali, alkaline earth and transition metal ions. The proposed electrodes have also been used for the direct determination of Pb2+ and Cu2+ ions in real samples.
Keywordsion-selective electrode lead copper
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