Phase-transfer catalysis of transmitters and pharmaceuticals at K+-valinomycin- and NH4+-nonactin-PVC-membranes of solid-state contact sensors

Summary As it is known that macrocyclic polyethers also complex substituted ammonium ions for PVC-membranes with the ammonium-selective nonactin and the potassium-selective valinomycin as carriers, the selectivity against transmitters and pharmaceuticals was determined. The tests were made with solid-state contacts independent of oxygen. With regard to the haemoanalysis the influence of pharmaceuticals on serum potassium measurements was determined with clinically significant concentrations of the pharmaceuticals. Apart from promethacine the greatest difference observed was 0.96%. Using the example of continuous monitoring of potassium in the heparinized blood of rats under the influence of epinephrine, it is shown that the decrease of potassium is clearly due to a metabolic effect of the catecholamine and does not represent an epinephrine interference at the sensor.