UREA SOLID-STATE BIOSENSOR SUITABLE FOR CONTINUOUS DIALYSIS CONTROL

A solid state potentiometric biosensor for urea determination was asse mbled coupling a nonactin-based ISE without an internal solution with immobilized urease. The system proved to be useful for continuous moni toring of urea during dialysis treatment using the ultrafiltrate of bl ood as sample. A noticeable shift of potential occurred during the dia lysis (probably due to continuous extraction of ionophore by the ultra filtrate). Therefore a flow injection analysis assembly was necessary to control the shift of electrode potential.