title: Simultaneous and sensitive analysis of aliphatic carboxylic acids by ion-chromatography using on-line complexation with copper(II) ion.
abstract: A new approach to ion chromatography is proposed to improve the UV detection of aliphatic carboxylic acids separated by anion-exchange chromatography. When copper(II) ion added to the mobile phase, it forms complexes with carboxylic acids that can be detected at 240 nm. The absorbance was found to increase with increasing copper(II) ion concentration. The retention times of α-hydroxy acids were also found to depend on the copper(II) ion concentration. Addition of acetonitrile to the mobile phase improved the separation of aliphatic carboxylic acids. The detection limits of the examined carboxylic acids (formate, glycolate, acetate, lactate, propionate, 3-hydroxypropionate, n-butyrate, isobutyrate, n-valerate, isovalerate, n-caproate) calculated at S/N=3 ranged from 0.06 to 3 μM. The detector signal was linear over three orders of magnitude of carboxylic acid concentration. The proposed method was successfully applied to analyze aliphatic carboxylic acids in rainwater and bread.
authors.affiliation: Toyama Institute of Health, 17-1 Nakataikoyama, Imizu 939-0363, Japan. Electronic address: tomoko.kenmei@pref.toyama.lg.jp.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Kemmei
authors.affiliation: Department of Chemistry, Faculty of Science, Tokai University, 4-1-1 Kitakaname, Hiratsuka 259-1292, Japan.
authors.forename: Shuji
authors.initials: S
authors.lastname: Kodama
authors.affiliation: Department of Biological Chemistry, College of Bioscience and Biotechnology, Chubu University, 1200 Matsumoto-cho, Kasugai 487-8501, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yamamoto
authors.affiliation: Products Planning & Development Dep. R & D Center, Nippon Filcon Co., Ltd., 2220 Ohmaru, Inagi 206-8577, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Inoue
authors.affiliation: Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan.
authors.forename: Kazuichi
authors.initials: K
authors.lastname: Hayakawa
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D001939:Bread / Q000032:analysis; D002264:Carboxylic Acids / Q000032:analysis* / Q000302:isolation & purification; D002852:Chromatography, Ion Exchange / Q000379:methods*; D003300:Copper / Q000737:chemistry*; D007477:Ions; D011422:Propionates / Q000032:analysis; D011891:Rain / Q000737:chemistry
chemical_list: D000097:Acetonitriles; D002264:Carboxylic Acids; D007477:Ions; D011422:Propionates; D003300:Copper; C032159:acetonitrile
keywords: Bread; Carboxylic acids; Copper(II) ion; Ion-exchange chromatography; Rainwater; UV detection