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 copolymer (I) can be used as a suitable ionophore to prepare a beryllium-selective PVC-based membrane electrode. The use of oleic acid (OA) and sodium tetraphenylborate (STB), as anionic additives, and dibutyl phthalate (DBP), dioctyl phthalate (DOP), acetophenone (AP) and nitrobenzene (NB), as plasticizing solvent mediators, were investigated. The best performance was observed with a membrane composition PVC:NB:I:OA of 3%:55%:10%:5% ratio. The resulting sensor works well over a wide concentration range (1.0×10-6 to 1.0×10-3M) with a Nernstian slope of 29mV per decade of Be2+ activity over a pH range 4.0-8.0. The limit of detection of the electrode is 8.0×10-7M (7.6ngml-1). The proposed electrode shows excellent discriminating ability toward Be2+ ion with regard to alkali, alkaline earth, transition and heavy metal ions. It was successfully applied to the determination of beryllium in a mineral sample.