Abstract

This is on hydrogen ion-selective memebrane electrodes which were made of tetrabenzylmethylenediamine (TBMDA), tetrabenzylethylenediamine (TBEDA), tetrabenzylpropylenediamine(TBPDA) and tetrabenzylhexylenediamine(TBHDA) as neutral carriers. Their response potentials to carbon number between amino groups showed linear selectivities to hydrogen ion in the range of pH 1~pH 9, pH 2~pH 9, pH 3~pH 9 and pH 4~pH 9 and slopes were 48mV/pH, 52mV/pH, 64mV/pH, 59mV/pH respectively. The interferences effect on the cations were measured to alkali metal ions(<TEX>$Li^+$</TEX>, <TEX>$Na^+$</TEX>, <TEX>$K^+$</TEX>), alkaline earth metal ions (<TEX>$Mg^{2+}$</TEX>, <TEX>$Ca^{2+}$</TEX>, <TEX>$Sr^{2+}$</TEX>, <TEX>$Ba^{2+}$</TEX>), transition metals ions(<TEX>$Cu^{2+}$</TEX>, <TEX>$Ni^{2+}$</TEX>, <TEX>$Co^{2+}$</TEX>) and anions(<TEX>$I^-$</TEX>, <TEX>$Br^-$</TEX>, <TEX>${NO_3}^-$</TEX>, <TEX>$SCN^-$</TEX>), and selectivity coefficients were measured by separate-solution method. The membrane electrode made of TBMDA among the electrodes showed the best selectivity in acidic solution.