A new selenite selective membrane electrode and its application

A new membrane ion selective electrode sensitive to selenite ion has been d eveloped. The electrode consisted of 1,2-phenylenediamine selen complex PIS (piaselenol) as the active material, PVC or SR (silicon rubber) as membran e matrix and DBF (dibutylphtalate) as plasticizer. This electrode showed li near response for selenite ion in the 10(-5)-10-M-1 concentration range. Th e slope of the linear portion was 21 mV/10-fold change in selenite concentr ation. The effect of membrane composition and membrane thickness on electro de response was studied and the electrode which contains 2% PIS, 49% PVC an d 49% DBF was found to be the most sensitive one to selenite. The slope of the electrode did not change for 2 months and the pH change did not affect the response of the electrode in pH range of 3-9. The interferences of SO42 -, SO32-, S2-, HPO4(2-), CI-, Br-, and I- are investigated and while no int erference was observed for SO42-, SO32-, S2- and I-, a very small interfere nce was observed for CI- and Br-. The selenium present in anodic slime is d etermined using this electrode. (C) 1999 Elsevier Science B.V. All rights r eserved.