Thiophene-based Schiff base ligand as ionophore for Ni(II)-selective polyvinyl chloride membrane electrode

Abstract

Abstract A synthesized Schiff base 2-acetylthiophene semicarbazone (3) was used for the preparation of Ni2+ selective polyvinyl chloride (PVC) membrane electrode. The prepared electrode with the optimized composition, PVC:3:sodium tetraphenylborate:di-n-butylphthalate as 33:6:3:58 exhibited a Nernstian response over the working range of 5.0 × 10−6–5.0 × 10−2 mol l−1 with a slope of 29.0 ± 0.3 mV/concentration. The electrode showed good selectivity towards Ni2+ with respect to several metal ions in the pH range of 2.5–10.0 in <15 s with a detection limit of 4.7 × 10−6 mol l−1. The electrode showed the additional benefit of working in partially nonaqueous media having up to 15% (v/v) methanol or ethanol. This electrode was also successfully applied in Ni2+ ion potentiometric titration with ethylenediaminetetraacetic acid as an indicator electrode.