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Journal Article 
Determination of Isopropyl Citrate in Edible Oil 
Shiyama, H; Nishijima, M; Yasuda, K; Kamimura, H; Tabata, S; Nishima, T 
Shokuhin Eiseigaku Zasshi / Journal of the Food Hygienic Society of Japan
ISSN: 0015-6426
EISSN: 1882-1006 
An analytical method was developed for the determination of isopropyl citrate in edible oil. The sample was dissolved in ethyl acetate and mono- and diisopropyl citrate were extracted with 5% sodium bicarbonate. The aqueous layer was acidified with phosphoric acid and isopropyl citrates were extracted with ethyl acetate. The ethyl acetate layer was dried with anhydrous sodium sulfate and evaporated to dryness. The residue was fluorescence-labeled with 4-bromomethyl-7-methoxycoumarin (Br-Mmc). Thin layer chromatography was used for the qualitative determination of fluorescence-labeled mono- and diisopropyl citrates. Qualitative determination was carried out as follows. The sample was hydrolyzed with potassium hydroxide solution. The hydrolyzed solution was washed with hexane and applied to the Amberlite IRA-402 column. Citric acid was eluted with 1 N hydrochloric acid. The eluate was evaporated to dryness, and the residue was dissolved in water. High performance liquid chromatography was used for quantitative determination of citric acid. The recoveries of isopropyl citrates added to edible oil were in the range from 84% to 93% and the detection limit of monoisopropyl citrate wasμg/g. © 1987, Japanese Society for Food Hygiene and Safety. All rights reserved. 
antioxidant; edible oil; high performance liquid chromatography; isopropyl citrate; thin layer chromatography