Experimental

An automated procedure for measurement of serum iron concentration is presented. Iron released from the serum transferrin by acid treatment in the presence of ascorbic acid was dialyzed into a buffer capable of maintaining the diffusate at a pH suitable for instantaneous and complete color formation with 4,7-diphenyl- 1,10 phenanthroline sulfonate. Procedural details, diffusability of iron, precision, and accuracy are de-scribed. ANTJMBER of manual methods and their modifications have been used for the determination of serum iron (1-6), but little has been accom-plished with automation. To effect this end, a manual procedure for serum iron determination (7) was combined with a modification of an automatic procedure for the determination of trace iron in aqueous sys-tems (8). The inclusion of a dialysis step resulted in a method which proved to be better than three other automatic and semiautomatic tech-nics investigated. These techmmics involved automated mneasurements of manually obtaimmed filtrates, continuously automated filtratiomi, (hm’ect color formation without filtration, or dialysis in lieu of filtration