A Spectrophotometric Assay of the Hill Reaction with Ferricyanide

Abstract

Spectrophotometric measurement of ferricyanide reduction by the Hill reaction is achieved by post illuminative addition of ferric chloride and orthophenanthroline. The resulting color is measured at 510 millimicrons. Ferricyanide reduction by sonicated chloroplasts is found to be proportional to chlorophyll concentration, length of light exposure, and is approximately equivalent to reduction of 2,3,6-trichlorophenol-indophenol dye.