Minimization of the acetate interference of calcium-selective carrier-PVC-membrane electrodes for process-controlled haemodialysis

Summary Up to now calcium-selective electrodes with carrier-PVC-membranes have shown a need for correction during their application in controlling the process at an artificial kidney, for the presence of acetate anions leads to immense differences of measurements because of the anion interference. On the basis of experimental research the membrane characteristics could be changed in such a way that there is no need to correct the measurements when the electrodes are used during bicarbonate haemodialyses with 2 mmol/1 acetate. This was achieved by optimizing the ratio of the concentration of synthetic, electrically neutral carrier and lipophilic anion and by using plasticizer effects. A special membrane was developed in the same way for an application in dialysis solutions with 35 mmol/l acetate.