Abstract: Objective:To explore a simple and practicable ion chromatography method for simultaneous determination of sodium,potassium,magnesium and calcium in milk powder. Methods:After being dialyzed,milk powder solution passed through C18 column,and then the sodium,potassium,magnesium and calcium in the effluent was simultaneously detected with 20 mmol/L CH3SO3H as eluent. Results:The dynamic balance period is only two hours or so at the stirring speed of 200 r/min and room temperature. The peak shapes of the four ions are perfect without big disturbance. Their relative standard deviations are all below 5% and their average recovery rates are all between 95 % and 105%. Conclusion:Ion chromatography is suitable to the simultaneous determination of sodium,potassium,magnesium and calcium in milk powder.

Key words: ion chromatography, milk powder, dynamic dialysis