Unknown Precipitate

To form the iron-curcumin complex, stoichiometric ratios are calculated and volumes of curcumin solution and iron solution are mixed.  Before the iron is added to the curcumin, the pH of the curcumin is adjusted to approximately 7.5 with triethylamine.  It was observed that when this solution is left overnight, a precipitate appears.  When centrifuged, it was discovered that the precipitate was actually a denser fluid and not a solid.  This dense fluid was dark in color and oily in consistency.  It was not soluble in the solvents typically used for FeCl₃ or curcumin.  After testing the oily fluid using HPLC it was discovered that it was not the iron-curcumin complex as had been reported in several papers, but just iron hydroxide.  

In order to further prove that the oily precipitate is not the iron-curcumin complex, different ratios of curcumin and iron(III) were mixed.  If the dense oil is iron hydroxide, then the test tubes containing more iron will have more precipitate.

7/31/18

-Alex Griffith