Improved potentiometric determination of potassium in whole blood and serum with a valinomycin-treated silicone-rubber tubular electrode

Tubular potassium-selective flow-through electrodes were obtained by treating silicone-rubber tubing with a solution of valinomycin in chloroform. They were compared with conventional PVC-based electrodes in a flow-through cell. When serum and whole blood were pumped continuously for 30 min and 5 h, the response and wash times for the electrodes were found to vary considerably. The silicone rubber-based potassium sensor showed better biocompatibility with virtually unchanged dynamic features after prolonged contact with blood.