PURPOSE: To minimize disturbance of K ion to the electrode, by providing a sensitive membrane wherein a specified amount of trimethylolpropane derivative giving an Na ion-selective sensitive group and an organic Na compound are dispersed in a high-molecular material.
CONSTITUTION: This Na ion-selective electrode is provided with a sensitive membrane formed by dispersing Na ion-selective sensitive groups in a high-molecular material as follows. The sensitive membrane is made up of a high-molecular membrane containing tris-ortho-( normal-benzoylacetanilide )-1,1,1-trimethylolpropane at the concentration by weight of 5W20% with respect to the total membrane, giving an Na ion-selective sensitive group and an organic Na compound. The Na ion-selective electrode provided with the sensitive membrane shows a selection coefficient with respect to K ion of about 1/10 to that with respect to Na ion, making it suitable for measuring samples of a living body.
KAWANA HIDEJIROU
MIYAGI HIROYUKI
TAKADA YOSHITADA
