We have tried to cotinuos monitoring of sodium ion, potassium ion concentrations and urea in the blood without sampling blood but connecting ultrafiltration cell to the patient's blood circulation. In this study measurment of chloride ion was added on this blood chemical monitoring system. Referance electrode of chloride ion was improved because of leakage of chloride ion from reference electrode. Basal problemes was examined by using these gel reference. And flow system of this blood chemical monitoring was improved, stability, the degree of accuracy and reproductivity were increased. There are size of electrode, shape of electrode and the methode to flow sample as improved points.
