Interference in the determination of potassium and sodium in foods for special medical prescription by flame atomic absorption and elimination

The studies of determination of potassium and sodium in food for special medical purposes showed that there were serious interferences, and results false increased.The interferences were eliminated by using ionization suppressant such as 0.15% cesium chloride or 0.05% strontium chloride solution.The linear range of potassium and sodium were 0.50 ~ 3.00 and 0.40 ~ 1.40μg /mL, the linear regression equation of potassium and sodium were y = 0.0092 + 0.1794x and y = 0.1019 + 0.4592x, the correlation coefficient of potassium and sodium were r = 0.9996 and r = 0.9991, the detection limit of potassium and sodium were 0.03 and 0.01μg /mL.This method showed good repeatability, the RSD of potassium and sodium were 4.10% and 3.81%, and high recovery rate potassium and sodium were 94.74% to 107.89% and 95.33% to 106.66%, respectively.This method improved precise and accuracy for the quantitative determination.