The Preparation Am) Storage of Vitamin C Concentrates from Lemon Juice*

The object of this investigation has been to study (a) the conditions necessary for obtaining precipitation of vitamin C with basic lead acetate, (b) the use of n-butyl alcohol as a solvent, and (c) the stability of purified preparations stored in the laboratory. The general method employed for concentrating and assaying the antiscorbutic factor from lemons’ was the same as that previously reported from this laboratory (l-3). There has been no difficulty in obtaining almost complete recovery of activity by a second precipitation with lead by any of five independent workers in our laboratory over a period of several years, but it is evident from the experience of another laboratory (4) that using somewhat different reagents does not lead to such recovery. The pH of the solutions from which active precipitates were obtained has been carefully rechecked in confirming our earlier reports. Practically the only change in procedure found necessary to avoid serious loss in the activity of preparations has been greater care in regard to the mechanical condition of residues from which the vitamin is extracted by organic solvents (2). Fresh test preparations were made weekly, which, after being freed from toxic reagents or solvents used, were made up to a standard volume in slightly acidic aqueous solution, placed in vials containing sufficient quantities for 1 day’s feeding, stoppered securely, and stored either in a refrigerator under carbon dioxide or nitrogen gas or in a desiccator with solid carbon dioxide.2