Metal Chelate Compounds of Tetracycline Derivatives. VIII

Colorimetric Determination of Tetracycline with Boric Acid

Abstract

Tetracycline, like chlortetracycline, reacts with boric acid in conc. sulfuric acid to form an orange-red chelate compound showing absorption maximum at 500 mμ. This fact was utilized in colorimetric determination of tetracycline and it was quantitated in a concentration range of 5-35 γ/cc. as tetracycline hydrochloride. Concentration of sulfuric acid was found to have a fairly great effect but the chelate compound was stable in a concentration above 85%. The procedure in the case of tetracycline is much more simple than that with chlortetracycline.