Ion selective electrodes(ISEs)are currently finding a widespread use for direct determination of ions inenvironmental Analysis[1-4].In compared to otheranalytical sensors,ion selective electrodes haveadvantages including simplicity ,speed and lowcost.These tools are mainly designed for using inaqueous solutions.In present work,we have studid the preparation anddesighning a coated membrane electrode for measuringthe uranyl cation in aqueous solutions. A large amount of166uranium in drinkingwater may lead to harmful biologicaleffects in humans. The chemical toxicity caused bynatural uranium gives a major risk to the kidneys. Thusthe constant monitoring of uranium in different matrixesis essential [5,7].The electrode was prepared by coating thesurface of a graphit by a membrane containingdioctylphtalat(DOP),B15C5 and carbon powder inpoly(vinyl chloride)(PVC) in tetrahydrofuran(THF). The best composition of coated membrane(w/w)wasfound:4%ionophore,20%plasticizer,56%pvc and 20%carbon powder.The electrode exhibits a nerenstianslope(31±2mv) over the concentration range 1×10-4 to1×10-1M.The effects of the PH and possible interferingcations and anions were investigated and optimizedcondition for electrode were evaluated.

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