1Department of Chemistry, Faculty of Samen Hojaj, Technical and Vocational University, Tehran, I.R. IRAN
2Department of Chemistry, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad, I.R. IRAN
3Department of Biochemistry, National Research Institute for Genetic Engineering and Biotechnology, Tehran, I.R. IRAN
4Department of Chemistry, Neyshabour Science and Research Branch, Islamic Azad University, Neyshabur, I.R. IRAN
Carbon paste electrode was modified by disodium 2,4-diamino-7-methylbenzo[g] pteridine-5,10-dioxide to fabricate a sensor for potentiometric determination of vanadyl ion (VO2+) in aqueous medium. The new ligand was synthesized in three steps with high yield. The optimal composition of the carbon paste was made of graphite powder (64.5%), ionophore (16.6%), paraffin oil (17.8%), and sodium tetraphenylborate (NaTPB, 1.1%). The electrode exhibited a constant sensitivity of 30.20 ± 0.5 mV to VO2+ ions over a concentration range of 5 mM to 1 mM. The detection limit was calculated to be 5 mM with a response time of less than 35 s. The electrode showed to be highly reproducible over a period of 3 weeks. This sensor exhibits high selectivity to VO2+ ions and was successfully employed for potentiometric titration of VO2+ ions with EDTA.
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