Investigating of Potentiometric Titiration of a modified carbon nanotube sensor based on N-quinoline-2-carboxamido-8-aminoquinoline

Potentiometric sensors have shown to be very effective tools for analysis of a wide variety of metal ions. Among them, carbon paste electrods (CPEs) have attracted interest as a result of their improved renewability, stable response, and low ohmic resistance compared to membrane electrodes. N-quinoline-2 carboxamido-8-aminoquinoline (QCA) seemed to be a suitable ion carrier for metal ions due to the presence of intermediate donating N atoms in its structur. Preliminary solution study shows the selectivity of (QCA) toward Ho3+ (III) ions in comparison of other common cations, including alkali, alkaline earth, transition and heavy metal ions. To have a long – term stable electrode for potentiometric uses, (QCA) was applied as ionophore in preparation of a nano-composite carbone paste electrode. This electrode was used as an indicatore electrode in the potentiometric titration of Ho3+ (III) ions with EDTA.