Determination of Cr(VI) with Spectrophotometry in KI-Starch System

A new determination method of chromium(Ⅵ) was astablished with spectrophotometry based on the reaction of KI and chromium(Ⅵ) in a solution of H 2SO 4,which gets iodine and turns starch solution into blue.The linear range of the determination is 0.09—1.04mg/L.The detection limit for chromium(Ⅵ) is 0.088mg/L.An apparent molar absorptivity is 4.94×10 4L·mol -1·cm -1.This method is simple and very sensitive,it is used for the determination of chromium(Ⅵ) synthetic sample with satisfactory results.