New diamino compound as neutral ionophore for highly selective and sensitive PVC membrane electrode for Be2+ ion

The complexation of synthesized diamine 2,6-bis[2-(o-aminophenoxy)methyl]-4-bromo-1-methoxybenzene with different ions was studied conductometrically. The best interaction was observed between the diamine and Be2+ ion and the formation constant of the resulting complex was evaluated. The suitability of the diamine compound as a beryllium ion carrier in a PVC membrane electrode for potentiometric determination of Be2+ ion was investigated. The prepared electrode, with optimum composition, exhibits a Nernstian response to Be2+ ion over a wide concentration range from 3.0 × 10−6 to 7.0 × 10−2 M and a very low detection limit of 2.0 × 10−6 M. It has an appropriate response time and suitable reproducibility, and can be used for a period of at least 1 month without any measurable divergence. The potentiometric response is independent of the pH of the test solution in the range of 4.0–7.0. The proposed sensor reveals good selectivity toward Be2+ ion with respect to many alkali, alkaline earth, transition and heavy metal ions. It was applied to the determination of beryllium in tap water samples and also samples containing interfering ions.