Additive-salt effect on low detection limit and slope sensitivity in response of potassium- and sodium-selective neutral carrier based electrodes and their liquid-membrane based ion-sensitive field-effect transistor

The remarkable effect of additive salts on low detection limits as weir as slope sensitivities were observed for the response characteristics of bis(crown) and valinomycin based poly(vinyl chloride) (PVC) membrane electrodes. The low detection limits and the slope sensitivities for bis(crown) and valinomycin based PVC membrane electrodes were improved apparently as the hydrophobicity of the additive salts increases. In order to clarify the effect of additive salts of the PVC membrane electrodes, the response characteristics of liquid-membrane, based K⁺ and Na⁺-ISEs, which were fabricated by using micro-ion-sensitive field-effect transistors (μ- ISFETs), were evaluated. The low detection limits and the slope sensitivities in the responses of the neutral-carrier based K⁺ and Na⁺-μ-ISFETs also changed remarkably with the kind as well as the ConcentratiOn of the additive salts.