Studies on the Photochemical Reaction of Fe(Ⅲ)-Citric Acid and Its Application

Under the conditions of pH 1.5 HNO medium Fe(Ⅲ)-citric acid complex was irradiated by ultravoilet light to form a red-voilet complex,the molar absorptivity of the complex is 1.360L/(mol.cm) at 400nm,Beer's law is obeyed in the range of 0.5～80 mg/L for citric acid.The method has shown that the advantages of this reaction are high sensitivity,good selectivity,simple and rapid,and has been applied to the determination of citric acid in drinking samples.