A Novel Wire-Type Lead-Selective Electrode Based on Bis (1'-Hydroxy-2'-Acetonaphthone)-2,2'-Diiminodiethylamine

The preparation of a lead-selective electrode based on bis(1'-hydroxy-2'-acetonaphthone)-2,2'-diiminodiethylamine (L) as sensing material is reported. The plasticized PVC membrane containing 30% PVC, 67% ortho-nitrophenyloctylether (NPOE) and 3% ionophore L was directly coated on a graphite rod. This electrode exhibits a nearly Nernstian slope of 27.8±0.2 mV decade^-1 over a concentration range 10^-6−10^-2 M with a detection limit of 4.0×10^-7 M. The response time of the electrode was found to be <20 s. The potential of the sensor was independent on pH variations in the range 5-7. The selectivity of the electrode towards lead ions over Na⁺, K⁺, Ag⁺, Ca²⁺, Sr²⁺, Fe²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, La³⁺, Sm³⁺ and Er³⁺ ions was investigated. The prepared electrode was successfully used as an indicator for titration of a lead solution with a standard solution of EDTA. The applicability of the sensor for Pb²⁺ measurement in various synthetic and real samples has been also demonstrated.