Determination of ionized magnesium in erythrocytes using a potentiometric analyzer Original Research Article

A simple method for the determination of ionized magnesium in erythrocytes using a potentiometric analyzer Microlyte 6 (Kone, Finland) was investigated. A set of aqueous solutions containing electrolytes at the same concentration as in erythrocytes in Tris/TES buffer (pH 7.2) was used as standards. The erythrocyte cell membranes were destroyed using three different methods: (A) HCl solution of pH 3.5, (B) dry ice–acetone mixture, (C) ultrasound. The result did not differ significantly between methods B and C (Student’s test, α=0.01). The results were compared with those obtained using the 31P nuclear magnetic resonance method (31P NMR). The dissociation constant of MgATP was calculated from the 31P NMR results. The results obtained from potentiometry and 31P NMR did not differ significantly (Student’s test, α=0.01). Total magnesium concentration was determined using atomic absorption spectrometry (AAS).