Ion-selective electrode based on polyurethane-immobilized di-(2-ethyl hexyl) phosphoric acid for low-concentration aqueous Pb2+ detection and quantification

This study used a polyurethane (PU)-based ion selective electrode (ISE) immobilized with di-(2-ethyl hexyl) phosphoric acid (D2EHPA) to detect and quantify Pb²⁺ ions at low concentrations (10⁻¹⁰ to 10⁻¹ M) in aqueous solution. PU, synthesized from castor oil (Ricinus communis L.), was utilized as the ISE membrane matrix. The ISE demonstrated a sensitivity of 26.24 ± 0.12 mV/decade, a detection limit of 1.44 × 10⁻⁷ M, and a response time of 10 s. We maintained the measurement stability for up to six days of storage.

The results of Pb²⁺ quantification produced by ISE were compared with the results using atomic absorption spectroscopy (AAS), indicating similar Pb²⁺ concentrations in both artificial and real wastewater samples (calculated t-value < theoretical t-value). Therefore, this ISE is suitable for detecting trace levels of Pb²⁺ and quantifying them with high accuracy.