Silver(I)-selective electrode based on [Bz₂Oxo₄(18)dieneS₄] tetrathia macrocyclic carrier
2006
Singh, Ashok Kumar | Saxena, Puja
A polystyrene-based membrane of 7,8:16,17-dibenzo-6,9,15,18-tetraoxo-1,5,10,14-tetrathiacyclooctadeca-7,16-diene [Bz₂Oxo₄(18)dieneS₄] was fabricated using sodium tetraphenylborate (NaTPB) and dioctyl phthalate (DOP) as anion excluder and plasticizing agent. The best performance was obtained from the membrane with the composition ionophore [Bz₂Oxo₄(18)dieneS₄]:polystyrene:DOP:NaTPB, 5:100:150:10 (w/w). The response of the electrode was linear over a wide range of concentration, 1.26x10-⁶-1.00x10-¹ mol L-¹ for silver ion with a Nernstian slope of 58.4±0.1 mV per decade and a detection limit of 1.0x10-⁶ mol L-¹. The electrode was found to be chemically inert and of adequate stability with a response time of 10 s and could be used for a period of 3 months without change of potential. It worked satisfactorily in mixtures containing up to 35% (v/v) non-aqueous content. The proposed membrane sensor had good selectivity for Ag⁺ over a wide variety of metal ions in the pH range 2.2-8.5. It was successfully used as an indicator electrode in potentiometric titration of silver ion. The electrode was also useful for determination of Ag⁺ in waste from photographic films.
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