Making a selective and sensitive iron (III) ion selection sensor based on nitrobenzo-18-crown-6 ionophore

摘要

Background: Electrochemical sensors are an important subgroup of chemical sensors in which an electrode is used as a signal transducer element. The purpose of the present study is to provide a new, simple and practical method for creating a sensitive sensor to a cationic pollutant of the iron (III) group. Methods: The penetration of the measured pollutant species into two levels of the membrane’s, interior and exterior, caused a potential difference in the membrane surface. This potential difference depended on the activity of the target species through the corrected Nicolsky-Eisenman equation and based on Nernst equations. Results: In this study, the selective iron (III) electrode based on a polymer membrane consisting of four main components of nitrobenzo-18-crown-6 ionophore, lipophilic additive potassium tetra case, 4-chlorophenyl borate (KTpClPB), and Ortho- nitro-phenyl octyl ether plasticizer (O-NPOE) in PVC with a weight percentage of 5, 1.5, 60.5, 33, respectively, showed a linear response with a Nernst slope of 19.77 ± 0.27 in the density range of 1.0 × 10 -6 – 1.0 × 10 -1 molar of iron (III) cation with a detection limit of 7.0 × 10 -7 in a pH-restricted range of 2.9-6.1. The average dynamic response time of the built-in electrochemical sensor was 15 seconds. Conclusion: The built-in sensor can be used for 12 weeks with acceptable repeatability. The made electrode has a very high selectivity for iron (III) cation in the presence of significant amounts of one, two, and three-valent intrusive ions of alkali metals, alkaline earth metals, intermediate metals, and heavy metals.