Analytical Sciences

[Tetrakis(4-N,N-dimethylaminobenzene)porphyrinato]manganese(III) Acetate as a Novel Carrier for a Selective Iodide PVC Membrane Electrode

Khalil FARHADI,*¹ Ramin MALEKI,*² Rouhollah HOSSEINZADEH YAMCHI,*¹ Hashem SHARGHI,*³ and Mojtaba SHAMSIPUR*⁴

*1 Department of Chemistry, Faculty of Science, Urmia University, Urmia, Iran
*2 Artemia & Aquatic Animals Research Center, Urmia University, Urmia, Iran
*3 Department of Chemistry, Faculty of Science, Shiraz University, Shiraz, Iran
*4 Department of Chemistry, Faculty of Science, Razi University, Kermanshah, Iran

[5,10,15,20-Tetrakis(4-N,N-dimethylaminobenzene)porphyrinato]Mn(III) acetate (MnTDPAc) was applied as an ionophore for an iodide-selective PVC membrane electrode. The influences of the membrane composition, pH of the test solution and foreign ions on the electrode performance were investigated. The sensor exhibited not only excellent selectivity to iodide ion compared to Cl^- and lipophilic anions such as ClO₄^- and salicylate, but also a Nernstian response with a slope of -59.4 ± 1.2 mV per decade for iodide ions over a wide concentration range from 1.0 × 10^-2 to 7.5 × 10^-6 M at 25°C. The potentiometric response was independent of the pH of the solution in the pH range of 2 - 8. The electrode could be used for at least 2 months without any considerable divergence in the potential. Good selectivity for iodide ion, a very short response time, simple preparation and relatively long-term stability were the silent characteristics of this electrode. It was successfully used as an indicator electrode in the potentiometric titration of iodide ions, and also in the determination of iodide from seawater samples and drug formulations.

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