Abstract:

Sodium ferric gluconate complex was prepared from D-sodium gluconate and FeCl3 using a simple synthesis
method. The appropriate level ranges for four independent variables, mass ratio of FeCl3 to sodium gluconate, reaction time,
temperature and starting pH, were determined by single factor experiments. Subsequently, these reaction conditions were
optimized by central composite and response surface methodology through second-order polynomial regression. The optimal
reaction conditions were established as follows: mass ratio of FeCl3 to sodium gluconate, 2.03:1; reaction time; 2.95 h;
starting pH, 11; and reaction temperature, 100 ℃. The iron content of the complex experimentally obtained under these
optimal conditions was 31.43%. The bias between the observed and predicted values of iron content was small, indicating
that the result was stable. The sodium ferric gluconate complex was confirmed by physicochemical properties and structural
characterization, which was characterized by chelated iron. This study can lay the scientific basis for developing oral
nutritional iron supplement containing sodium ferric gluconate. The optimized process is convenient and reasonable, having
great application potential and providing a new idea for the development of iron complexes.

Key words: sodium ferric gluconate complex, process optimization, central composite design, iron content, oral iron supplement