DDB liver drug as a novel ionophore for potentiometric barium (II) membrane sensor

Dimethyl-4,4-dimethoxy-5,6,5′,6′-dimethylene dioxy biphenyl-2,2-dicarboxylate (DDB) liver drug is used as a novel ionophore in plasticized poly (vinyl chloride) (PVC) matrix membrane sensors for barium ions. Optimum performance characteristics are displayed by membrane sensor incorporating DDB ionophore, potassium tetrakis(4-chlorophenyl)borate as lipophilic salt, and o-nitrophenyloctyl ether as plasticizer. The sensor exhibits a linear response over the concentration range 10−1–10−5 mol l−1 BaCl2 with a Nernstian slope of 30 mV per decade and high selectivity towards Ba2+ with respect to Li+, Na+, K+, Rb+, NH4+, Mg2+, Ca2+, Sr2+, Mn2+, Co2+, Ni2+, Cd2+, Al3+, La3+, and Ce3+ ions. The sensor response is stable over a wide pH range (4–9) and the lifetime is about 2 months. The proposed sensor is successfully applied to the determination of Ba2+contents of some rocks.