Fabrication of Novel Potentiometric Sensor for Lead Ion Detection in Blood Samples: Experimental and Theoretical Approaches

Abstract

One of the significant health problems in some developing countries such as Iran is lead toxicity. Potentiometric plasticizer-free Pb2+ selective electrode based on a simple and biocompatible ionophore, curcumin, for lead (II) detection in erythrocytes have been developed. Glassy carbon electrode modification was done with curcumin as an ionophore. Curcumin and its interaction with lead (II) were characterized using FT-IR, FE-SEM, and UV–Vis spectroscopic techniques. Match potential method (MPM) was applying for determining selectivity coefficients of the proposed sensor. Furthermore, the structures were optimized in various media for both tautomeric structures of curcumin, and then the binding mechanism was supported by DFT calculation, being in a high correlation and agreement by experiment. Also, noncovalent interaction studies were done to obtain a description of the sensing process. The fabricated ISE based on photocurable self-plasticizing (n-butylacrylate) membrane with curcumin shows a potentiometric response with a Nernstain slop of 28.348 ± 0.68 mV per decade in a linear range from 1.0 × 10-9 to 1.0 × 10-2 and detection limit of 3.98 × 10-10 M. The sensor' s response time was about 20 s at room temperature. The sensor shows a sensitive detection of Pb2+ in human erythrocytes and standard solutions.