title: Reversed phase liquid chromatographic determination of organic acids using on-line complexation with copper(II) ion.
abstract: We describe a simple and sensitive liquid chromatographic method for the analysis of organic acids using on-line complexation with copper(II) ion. Organic acids complexed with copper(II) ion were separated on a reversed-phase C18 column and detected by UV absorption at 240 nm. The copper(II) ion concentration in the mobile phase had a great influence on separation and sensitivity. A mobile phase consisting of 10 mM copper(II) sulfate in 5 mM sulfuric acid (pH 2.3) was used to separate nine organic acids (tartaric, malic, malonic, lactic, acetic, citric, maleic, succinic and fumaric acids). The detection limits of the examined organic acids calculated at S/N = 3 ranged from 0.6 to 100 μM. The detector signal was linear over three orders of magnitude of organic acid concentration. The method successfully measured organic acids in juice and vinegar samples.
authors: Toyama Institute of Health, 17-1 Nakataikoyama, Imizu 939-0363, Japan. Electronic address: tomoko.kenmei@pref.toyama.lg.jp.
authors: Tomoko
authors: T
authors: Kemmei
authors: Department of Chemistry, Faculty of Science, Tokai University, 4-1-1 Kitakaname, Hiratsuka 259-1292, Japan.
authors: Shuji
authors: S
authors: Kodama
authors: Department of Biological Chemistry, College of Bioscience and Biotechnology, Chubu University, 1200 Matsumoto-cho, Kasugai 487-8501, Japan.
authors: Atsushi
authors: A
authors: Yamamoto
authors: Department of Biological Chemistry, College of Bioscience and Biotechnology, Chubu University, 1200 Matsumoto-cho, Kasugai 487-8501, Japan.
authors: Yoshinori
authors: Y
authors: Inoue
authors: Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan.
authors: Kazuichi
authors: K
authors: Hayakawa
mesh_terms: D019342:Acetic Acid / Q000032:analysis*; D001628:Beverages / Q000032:analysis*; D002264:Carboxylic Acids / Q000032:analysis* / Q000302:isolation & purification; D003300:Copper / Q000737:chemistry*; D014466:Ultraviolet Rays
chemical_list: D002264:Carboxylic Acids; D003300:Copper; D019342:Acetic Acid
keywords: Copper(II) ion; Organic acids; Reversed phase liquid chromatography; Ultraviolet detection