Tripod Structure Of Compounds As The Carrier Ion-selective Electrode

Four novel PVC membrane ion-electrodes have been evaluated by using four new tripodal compounds EtC[CH2OCH2CON(CH2CH3)C6H5]3(Ll), EtC[CH2OCH2C ON(CH3)C6H5]3(L2), EtC[CH2OCH2CONC5Hio]3(L3), EtC[CH2OCH2CONH-Py-Z]3 (L4) as carriers and o-niteophenyl octyl ether(o-NPOE) as plasticizer for the analysis of monovalent alkali Li+ and Na+ and divalent alkaline earth Ca Sr Ba cations. The electrode based on tripodal ligand LI as carreier exhibits best response characteristics than on ligands L2, L3 and L4.The results showed that the electrode based on tripodal ligand LI as carrier, o-NPOE as plasticizer and KTpClPB as additive exhibits almost Nernstian response characteristics for Li+,Na+,Ca2+,Sr2+,Ba2+. The linear response range toward the cations is respectively. The corresponding dection limits are 5.8 and the corresponding slopes 28.6mv/dec with correlation coefficients of 0.9939 0.9856, 0.9999, 0.9999, 0.9999; The electrode can be used as calcium ion-selective electrode. The electrode based on DBP as plasticizer shows almost Nernstian response characteristics for Li+, Na+ with the corresponding slopes of 55.0, 53.2mv/dec, the linear range of 10-3-10-1, mol.l-1, the dection limits of 1.6X 10 2.1 X 10-4 ,the correlation coefficients of 0.9994, 0.9987 and can be used as Li+ ion-selective electrode. The response mechanism is investigated by use of two additive KTPC1PB and TDMAC1 and has been proved neutral carrier mechanism. The influence of pH, stability, reproducibility and lifetime were also studied.