The new methods of determination of Mg2+, Ca2+, Na+ and K+ ions in erythrocytes by ion selective electrodes

Intracellular ionized magnesium, sodium and potassium were determined using a clinical potentiometric analyzer with ion-selective electrodes. The results did not differ significantly compared with other methods (magnetic resonance spectroscopy (NMR), atomic absorption spectrometry (AAS), flame emission spectrometry (FES), inductively coupled mass spectrometry (ICP-MS), zero-point titration (ZPT)). An appropriate composition of the ion-selective membrane for intracellular calcium determination was found. The ionized magnesium determination in erythrocytes was successfully used in medical analysis of dialyzed and critically ill postoperative patients.