Ion-selective electrode based on polyurethane-immobilized di-(2-ethyl hexyl) phosphoric acid for low-concentration aqueous Pb 2+ 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 Pb 2+ 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 Pb 2+ quantification produced by ISE were compared with the results using atomic absorption spectroscopy (AAS), indicating similar Pb 2+ concentrations in both artificial and real wastewater samples (calculated t-value < theoretical t-value). Therefore, this ISE is suitable for detecting trace levels of Pb 2+ and quantifying them with high accuracy.