LINEARITY AND STABILITY OF THE AVL AND NOVA MAGNESIUM AND CALCIUM ION-SELECTIVE ELECTRODES

We studied the stability and linearity of the AVL and Nova Mg and Ca i on-selective electrodes and the relation between the ionized Ca and io nized Mg results reported by each analyzer, The response of the electr odes to different concentrations of Mg and Ca was determined for salin e solutions, aqueous solutions, and serum samples, The electrodes from both manufacturers demonstrated acceptable stability for the time of the study, The response of the electrodes was linear within the range specified by each manufacturer, but relative nonlinearity and the valu es for the linear limits differed between the AVL and Nova analyzers, The ionized Mg results varied with the concentration of Ca, The relati on between ionized Ca and ionized Mg results was nonlinear and differe d between the AVL and Nova electrodes, Intermethod comparison between the electrodes showed poor agreement for ionized Mg results, especiall y at low and high concentrations of total Ca and total Mg.