Coated-wire lithium ion-selective electrodes based on polyalkoxylate complexes

Abstract

Barium and lithium adducts of polyalkoxylates have been investigated as sensors in lithium ion-selective electrodes using a microconduit flow injection analysis system. Dioctyl phenylphosphonate (DOPP) and dioctyl 3-nitrophenylphosphonate (N-DOPP) were employed as solvent mediators. Selectivity coefficients, k^pot_Li,M, for the Ba(PPG 1025)_0.69. (TPB)₂-DOPP-based lithium electrode in 0.14 M sodium chloride solution are as follows: Na⁺ 3.7 × 10^–2, K⁺ 4.4 × 10^–3, Ca²⁺ 4.1 × 10^–1 and Mg²⁺ 8.0 × 10^–2. The selectivity coefficients are compared with those for two other previously reported lithium electrodes. The barium polyalkoxylate adduct is a better sensor for lithium than its lithium analogue.