Preparation and Characterization of a Mercury£¨¢ò£© selective Polymeric Membrane Electrode

KeyWord:ion selective electrode  mercury ion£¨¢ò£©  Schiff base

Abstract:

      A new Schiff base compound derived from 1£¬2£¬4 triazole was synthesized with a high yield.Potentiometric responses of poly£¨vinyl£© chloride£¨PVC£© electrode based on this ligand as neutral ionophore showed high sensitivity and selectivity towards Hg2+ ion.Effects of different plasticizers and amounts of ion exchanger on the potentiometric response property of Hg2+ selective electrode£¨Hg2+-ISE£© were discussed.The result indicated that£¬under the optimal membrane composition £ÛPVC£º32ª±70£¬o NPOE£º65ª±39£¬ionphore£º0ª±99£¬ion exchanger£º0ª±92£¬£¨w¡Ãw£©£Ý£¬a good Nernstian response slope of (29ª±3¡À0ª±3) mV/dec was obtained for Hg2+ in a wide concentration range of 1ª±0¡Á10-6-3ª±0¡Á10-4 mol/L with a detection limit of 2ª±6¡Á10-7 mol/L ª±Except for silver ion£¬most of alkali metal£¬alkaline earth metal and other common transition metal ions didn¬ðt interfere the performance of the membrane electrode.The fabricated Hg2+-ISE can be used in a wide pH range of 2ª±8-5ª±6 with a fast response time of less than 12 s and can be used for 3 month without any obvious change in potentiometric response.The proposed electrode was also successfully applied as indicator electrode in the potentiometric detection of Hg2+ in lab water by standard addition method and the results were confirmed by ICP-MS.