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

Abstract

Ion-selective electrodes are now widely used for the determination of specific ions in solution and have found widespread applications in analytical chemistry. 1 In recent years, the study of anti-Hofmeister sensing materials with high selectivity for given anions is an expanding domain in chemical sensors.It is well-known that the use of methalloporphyrins as ionophores in polymeric membrane electrodes can induce potentiometric anion selectivity patterns that differ significantly from the classical Hofmeister pattern. The observed selectivity for metalloporphyrins is not governed by anion lipophilicity, as in the case of a dissociated ion-exchanger, but by specific chemical interactions between the metalloporphyrins in the membrane and the anions in the sample solution, such as complex formation or coordination. [2][3][4][5][6][7] Moreover, membranes constructed based on metalloporphyrins in different matrixes such as PVC, silicon rubber or polyurethane, showed different selectivity toward anions.1 Meyerhoff et al. illustrated that not only the porphyrin structure, but also the nature of the axial linked anion play an important role in the potentiometric selectivity. 6,7 Therefore, considering these results, a wide variety of polymeric membranes based on metalloporphyrins or other ionophores have been developed for iodide, as described in the literature. [8][9][10][11][12][13][14][15][16][17][18][19][20][21] To the best of our knowledge, only one iodide-selective membrane electrode based on the Mn(III)-porphyrin derivative supported in polystyrene pyridine copolymer (MnP-PSP4) has been reported until now. 17 We recently used tetrachlorophenylporphyrinato Mn(III) as a new ionophore in constructing of a triiodide PVC membrane electrode, 22 and also reported on a novel class of triiodide membrane electrodes using ion pairs of imidazole antifungal drugs (ketoconazole and clotrimazole) with triiodide as suitable carriers. 23,24 Due to the vital importance of iodide in biological fluids and drug preparations, on one hand, and also the develoment of new simple methods in the determination of iodide at low concentrations, on the other hand, in the present work we reported on a new highly selective PVC membrane electrode based on recently synthesized [5,10,15,20-tetrakis(4-dimethylaminobenzene)porphyrinato]manganese(III) acetate (MnTDPAc) (Fig. 1) as an ionophore. The proposed electrode is the first attempt to construct an iodide membrane electrode based on Mn(III)-porphyrin derivatives in a PVC matrix. Applications of the proposed membrane electrode as an indicator electrode in the potentiometric titration of iodide ions, pharmaceutical preparations and in the direct potentiometric determination of iodide in seawater samples were investigated. [5,10,15,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 n...

Ion Recognition: Application of Symmetric and Asymmetric Schiff Bases and Their Complexes for the Fabrication of Cationic and Anionic Membrane Sensors to Determine Ions in Real Samples

“…Another iodide sensor was described by Farhadi et al in 2004. This sensor was used for the determination of iodide in seawater samples and drug formulations [98]. The most recent work on I -sensors was conducted by Zare et al in 2005. In this work, a linear dynamic range of 5.0 10 -7 to 1.0 10 -1 M with a Nernstian slope of -58.9 mV decade -1 was obtained.…”

“…In the next year, Ganjali et al prepared an iodide ISE based on a cerium-salen complex that presented a Nernstian slope of 57.5 mV decade -1 [97]. Another iodide sensor was described by Farhadi et al in 2004. This sensor was used for the determination of iodide in seawater samples and drug formulations [98].…”

Supramolecular Based Membrane Sensors

“…There have been reports on the application of porphyrin metal complexes (Figures 24, 25) for the detection of other anions like Cl - [88-90] Br - [91-93], I - [93-95], I 3- [96], arsenite [97], SCN - [98, 83], dinitro benzoate [99], histidin [100], nitrite [101], NO 3 - [102]. …”

One decade of research on ion-selective electrodes in Iran (1996–2006)

“…Sensors for the lipophilic ClO 4 -have also been constructed based on Ni(II)-hexaazacyclotetradecane [230], phosphorus(V)-tetraphenylporphyrin [231], cobaloxime [232], 1,3,5,8,10,13-hexa-azacyclotetradecane [233], 1,8-tert-butyl-1,3,5,8,10,13-hexa-azacyclotetradecane [233], and two nickelhexaazamacrocycles [234]. The only Cl -sensor was based on a thalium(III) Schiff's base [245] with no considerable interferences, which had a detection limit of 2.0 × 10 -6 M. The other halogen sensors include Br -ion PMEs [246][247][248], based on -phenyldibenzo[a]xantheniumbromide [236], bis(4-hydroxyphenyl)-1,4-diaza-1,3-butadiene-Hg(II) [237], iron(III)-salen [238], which suffer interferences only from NO 3 -, Cl -, I -, SCN -. Iodine sensors were more in number , and have been mostly PMEs, although they include some CGEs.…”