Beryllium-selective membrane sensor based on 3,4-di[2-(2-tetrahydro-2H-pyranoxy)]ethoxy styrene-styrene copolymer

We found that 3,4-di[2-(2-tetrahydro-2H-pyranoxy)]ethoxy styrene-styrene co polymer (I) can be used as a suitable ionophore to prepare a beryllium-sele ctive PVC-based membrane electrode. The use of oleic acid (OA) and sodium t etraphenylborate (STB), as anionic additives, and dibutyl phthalate (DBP), dioctyl phthalate (DOP), acetophenone (AP) and nitrobenzene (NB), as plasti cizing solvent mediators, were investigated. The best performance was obser ved with a membrane composition PVC:NB:I:OA of 3%:55%:10%:5% ratio. The res ulting sensor works well over a wide concentration range (1.0 x 10(-6) to 1 .0 x 10(-3) M) with a Nernstian slope of 29 mV per decade of Be2+ activity over a pH range 4.0-8.0. The limit of detection of the electrode is 8.0 x 1 0(-7) M (7.6 ng ml(-1)). The proposed electrode shows excellent discriminat ing ability toward Be2+ ion with regard to alkali, alkaline earth, transiti on and heavy metal ions. It was successfully applied to the determination o f beryllium in a mineral sample. (C) 2001 Elsevier Science B.V. All rights reserved.