New modified selective platinum electrode based on poly (ethylene glycol) for Iron (III) detection in real water

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Purpose – This work aims to determine iron (III) in real water by using a new amperometric sensor on the basis of polyethylene glycol (PEG) to test and characterize a new modified selective platinum electrode. Design/methodology/approach – In this review, the authors focus on testing and characterizing several polymeric membranes by using cyclic voltammetry and square-wave voltammetry (SWV) methods to differentiate the nature of plasticizers (2-Nitrophenyl octyl ether [NPOE], Di-n-octyl phthalate, Bis (2-ethylhexyl) sebacate, PEG. The authors have evaluated the possibility of using crown ether and three zeolite ionophore (faujasite [FAU], Chabazite and ZSM-5) matrixes as novel materials for the selective determination of iron (III) using SWV for the best membranes. Findings – The results demonstrated that the modified platinum electrode presents linear dependence of amperometric signal with a wide linear range of 10 9 to 10 4 mol.L 1 for iron determination, revealing a detection limit of 10 10 mol.L 1 and amperometric sensibility of 58.58 mA/mol. L 1 . The slope of the membrane plasticized with PEG calibration curve is six times higher than that of the other membranes. It was noticed that when the crown ether and the three zeolite ionophores were used, as a new detective material for iron with the membrane plasticized with PEG, the expected results were highly proven. The modified platinum electrode showed high selectivity to iron (III) when the heavy metal ions such as Ni (II), Al (III), Zn (III), Cd (II), Gd (II) and Cu (II) were present. Originality/value – The utility of the method and the efficiency of the best membrane sensor have been accurately tested by the determination of iron in real water samples of Hassi Messaoud, south of Algeria.
Crown ether is a successful neutral carrier when it is used to detect the production of iron (III)-selective membrane electrodes. Among all tested sensing matrices, the membrane based on PVC/PEG/TBATPB/crown ether exhibits the best electrochemical performances in terms of sensitivity and stability. The modified electrode shows high stability in repetitive experiments owing to good adhesion and high affinity of the sensing membrane towards the iron (III) ions. This behaviour can be explained by the formation of complexes. The developed electrode showed an attractive candidate as an iron (III) sensor for practical analysis applications. The optimized formulation of the membrane (i.e. 29-mg PVC, 67-mg PEG, 2-mg TBATPB, 2-mg benzo-18-crown- 6) resulted in a linear concentration range of 10 9 to 10 4 mol.L 1 with a slope of 58.58 mA/mol.L 1 and an LOD of 10 10 mol.L 1. These results could help us to choose the best plasticizer (PEG) with suitable concentration in real water. As a result, the validity of the used electrochemical method and the applicability of the ion sensor were successfully tested by the determination of iron (III) ions in several real water samples of the ZCINA, located in the north of Hassi Messaoud, south of Algeria. The preparation of the electrode is simple, not expensive.
Citation SR-01-2017-0020