Flame photometric and atomic absorption determination of calcium, potassium, and sodium in Ringer's solution and injection and in lactated Ringer's solution.

Authentic and commerical counterparts of Ringer's solution and lactated Ringer's solution were analyzed by 14 collaborators. Calcium, potassium, and sodium were to be determined by any flame emission or atomic absorption instrument operated at prescribed performance levels, and basic procedures for comparing samples and standards were also given. Recoveries of the cations from authentic and commercial solutions were as follows: calcium 95.6-102.1 and 95.6-103.6%, respectively; potassium 97.9-101.7 and 98.7-102.4%; sodium 98.2-103.1 and 97.3-103.7%. The results indicate that the method yields acceptable precision for the determination of the 3 cations in fluid and electrolyte replenishers. The method has been adopted as official first action.