POTENTIOMETRIC DETERMINATION OF TOTAL AND IONIZED CALCIUM IN OSTEOBLAST-LIKE CELL-CULTURE MEDIUM

The effect of the ionic strength and composition of solutions in the d irect potentiometric determination of total and ionized calcium conten t using a calcium selective electrode was investigated. In the presenc e of a constant complexation buffer (CCB), the addition of sodium chlo ride and sodium bicarbonate causes a decrease in the limit of detectio n of the potentiometric response. When the procedure was tested in ost eoblast-like cell culture medium no electrode interferences or method interferences were observed by the presence of proteins, i.e., the tot al and ionized calcium in this medium can be measured by potentiometri c means.