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 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. • D2EHPA is responsible for attracting the Pb 2+ analyte. • The optimum sensitivity after the addition of TISAB was 27.11 ± 0.11 mV/decade. • The linear range of the D2EHPA/polyurethane-based Pb 2+ ISE was 10 −7 –10 −1 M. • The limit of detection was 1.44 x 10-7 M with a lifetime of 6 days. • Pb 2+ quantification obtained from the ISE was similar to that obtained from AAS.