title: Simple and effective label-free capillary electrophoretic analysis of sugars by complexation using quinoline boronic acids.
abstract: An effective separation and detection procedure for sugars by capillary electrophoresis (CE) using a complexation between quinolineboronic acid (QBA) and multiple hydroxyl structure of sugar alcohol is reported. We investigated the variation of fluorescence spectra of a variety of QBAs with sorbitol at a wide range of pH conditions and then found that 5-isoQBA strongly enhanced the fluorescence intensity by the complexation at basic pH conditions. The other sugar alcohols having multiple hydroxyls also revealed the enhancement of the fluorescence intensity with 5-isoQBA, whereas the alternation of the intensity was not found in the sugars such as glucose. After optimization of the 5-isoQBA concentration and pH of the buffered solution in CE analysis, 6 sugar alcohols were successfully separated in the order based on the formation constants with 5-isoQBA, which were calculated from the variation of the fluorescence intensity with each sugar alcohol and 5-isoQBA. Furthermore, the limits of detection for sorbitol and xylitol by the CE method were estimated at 15 and 27 μM, respectively.
authors.affiliation: †Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Kubo
authors.affiliation: †Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Kanemori
authors.affiliation: †Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Risa
authors.initials: R
authors.lastname: Kusumoto
authors.affiliation: ‡Laboratory for Integrated Biodevice Unit, Quantitative Biology Center, RIKEN, Chuo-ku, Kobe, Hyogo 650-0047, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Kawai
authors.affiliation: §Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Sueyoshi
authors.affiliation: †Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Toyohiro
authors.initials: T
authors.lastname: Naito
authors.affiliation: †Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Otsuka
mesh_terms: D001897:Boronic Acids / Q000737:chemistry*; D019075:Electrophoresis, Capillary / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D011804:Quinolines / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013402:Sugar Alcohols / Q000032:analysis* / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D001897:Boronic Acids; D011804:Quinolines; D013402:Sugar Alcohols; C037219:quinoline