Rapid Determination of Milk Salts and Ions. I. Determination of Sodium, Potassium, Magnesium, and Calcium by Flame Spectrophotometry

Abstract

Summary A rapid determination of milk cations is presented. A trained technician can make four to six complete analyses a day for sodium, potassium, calcium, and magnesium. The cation exchange resin Dowex 50 is used to eliminate, quantitatively, the total amount of cations from a milk serum prepared according to the procedure of Jenness (2) and Murthy and Whitney (4) . Then, the cations are quantitatively eluted with 3.5 N HCl and analyzed by flame spectrophotometry. The accuracy of the method is due to the fact that the analyzed solution does not contain other substances than the cations to be analyzed—hydrochloric acid and ammonia. The interference of phosphoric acid, especially, and of organic materials, is avoided.