RESUMO
The method of determination of potassium, sodium, calcium and magnesium cations by capillary zone electrophoresis (using lithium cations as the internal standard) in the juices and nectars was advised. Optimal conditions for electrophoretic separation: pH value of the working buffer (pH 3.6), the concentration of imidazole (contrast agent 15-20 mmol/dm3), the concentration of 18-crown-6 ether (2 mmol/dm3). The method was tested on 15 samples of juices and nectars. The results of determination of potassium and magnesium cations were compared with results obtained by mass spectrometry with inductively coupled plasma. The equation of the linear regression and R-squared value for determinations of magnesium cations were defined as: y = 0.999x + 3.29; R = 0.952; for determination of potassium cations: y = 0.959x + 51.94; R = 0.997; indicating good the correlation between the data obtained by these methods.
