Potentiometric behavior of N,N,N',N'-tetrabenzylmethylenediamine-based hydrogen ion-selective electrodes

H(+)-ion selective electrodes (H(+)-ISE) based on N,N,N',N'-tetrabenzylalkylenediamine (alkylene: methylene, ethylene, propylene, hexylene) are prepared. We are compared with their response potentials to carbon numbers between diamino groups. They were showed linear selective to hydrogen ion in the range of pH 1.5-9.0, 2.5-9.0, 3.5-9.0 and 4.0-9.0, and their Nernstian slopes were 57.3, 53.5, 57.4 and 56.1 mV pH(-1) at 20+/-0.2 degrees C (theoretical value: 58.2 mV pH(-1)), respectively. The interference effect on the cations were measured to alkali metal ions, alkaline earth metals ions. Selectivity coefficients were measured by the mixed-solution method. Among all electrodes the N,N,N',N'-tetrabenzylmethylenediamine (TBMDA)-based electrode has shown the best selectivity in acidic solution.