Thallium (I) Selective Membrane Sensor Using Newly Synthesized Podand Derivative of Catechol and Quinoline

The podand chelate, 1,2-bis[ 2' -(8 -oxyquinoline)ethoxy]-benzene have beensynthesized and used as a neutral ionophore to construct an ion selective electrode for thepotentiometric determination of thallium ions. due to the decisive role of solvent mediators,the membranes was fabricated with the plasticizers o-npoe, dbp, dbbp, tep, oa, dop,cn respectively and anionic additive natpb. the best of the results were obtained with themembrane electrode composition of o-npoe:pvc:ionophore:natpb (58%:34%:5%:3%).this sensor exhibits nernstian response with slope 58.7±0.3 mv decade-1 of activity inconcentration range 2.0×10-9 to 1.0×10-1 m tl(i), performs satisfactorily over wide ph range( 2.5-12), with a fast response time (5 s). the sensor was also found to work satisfactorily inpartially non-aqueous media up to 40% content of methanol, ethanol, acetone and acetonitrilesolution. the tl(i)-selective electrode was used as an indicator electrode for the titration oftlno3 with edta and ki solution. the selectivity coefficients determined by using fixedinterference method (fim) indicate high selectivity for tl (i)