ABSTRACT
The reasonable selectivity of calcium-ion-selective membrane sensor toward typical components of blood serum led to numerous applications in biomedical sciences and also to its use in analytical, inorganic, organic, and physical chemistry. Aluminum in antacid formulations is mostly present in non-ionic form, as hydrated aluminum oxide. Ammonia-gas-sensing probes use a hydrophobic gas-permeable membrane to separate the alkaline test solution from the internal solution. In most cases calcium is determined after solubilization of the sample with dilute hydrochloric acid, adjustment of the pH of the solution to 10 to 11 with ammonia buffer, and titration with EDTA standard solution in the presence of a calcium-ion-selective membrane sensor. The intereference of iron(III) with the solid-state copper(II)-ion-selective sensor has been used to determine iron(III) by direct potentiometry. The principal interferente of sodium glass electrodes are hydrogen and silver ions; potassium ions interfere to a lesser extent.
