title: Automatic analyzer for highly polar carboxylic acids based on fluorescence derivatization-liquid chromatography.
abstract: A sensitive, versatile, and reproducible automatic analyzer for highly polar carboxylic acids based on a fluorescence derivatization-liquid chromatography (LC) method was developed. In this method, carboxylic acids were automatically and fluorescently derivatized with 4-(N,N-dimethylaminosulfonyl)-7-piperazino-2,1,3-benzoxadiazole (DBD-PZ) in the presence of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride by adopting a pretreatment program installed in an LC autosampler. All of the DBD-PZ-carboxylic acid derivatives were separated on the ODS column within 30 min by gradient elution. The peak of DBD-PZ did not interfere with the separation and the quantification of all the acids with the exception of lactic acid. From the LC-MS/MS analysis, we confirmed that lactic acid was converted to an oxytriazinyl derivative, which was further modified with a dimethoxy triazine group of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMT-MM). We detected this oxytriazinyl derivative to quantify lactic acid. The detection limits (signal-to-noise ratio = 3) for the examined acids ranged from 0.19 to 1.1 µm, which correspond to 95-550 fmol per injection. The intra- and inter-day precisions of typical, highly polar carboxylic acids were all <9.0%. The developed method was successfully applied to the comprehensive analysis of carboxylic acids in various samples, which included fruit juices, red wine and media from cultured tumor cells.
authors.affiliation: Laboratory of Analytical and Bio-Analytical Chemistry, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan.
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Todoroki
authors.forename: Tatsuki
authors.initials: T
authors.lastname: Nakano
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Ishii
authors.forename: Kanoko
authors.initials: K
authors.lastname: Goto
authors.forename: Ryoko
authors.initials: R
authors.lastname: Tomita
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Fujioka
authors.forename: Jun Zhe
authors.initials: JZ
authors.lastname: Min
authors.forename: Koichi
authors.initials: K
authors.lastname: Inoue
authors.forename: Toshimasa
authors.initials: T
authors.lastname: Toyo'oka
mesh_terms: D001331:Automation; D001628:Beverages / Q000032:analysis; D002264:Carboxylic Acids / Q000032:analysis* / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods*; D002853:Chromatography, Liquid / Q000379:methods; D003470:Culture Media / Q000032:analysis / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry; D005638:Fruit / Q000737:chemistry; D006801:Humans; D057230:Limit of Detection; D009025:Morpholines / Q000737:chemistry; D010069:Oxadiazoles / Q000737:chemistry; D010879:Piperazines / Q000737:chemistry; D015203:Reproducibility of Results; D059629:Signal-To-Noise Ratio; D013449:Sulfonamides / Q000737:chemistry; D053719:Tandem Mass Spectrometry / Q000379:methods; D014407:Tumor Cells, Cultured; D014920:Wine / Q000032:analysis
chemical_list: C467606:4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride; D002264:Carboxylic Acids; D003470:Culture Media; D005456:Fluorescent Dyes; D009025:Morpholines; D010069:Oxadiazoles; D010879:Piperazines; D013449:Sulfonamides; C076762:4-(N,N-dimethylaminosulphonyl)-7-(1-piperazinyl)-2,1,3-benzoxadiazole
keywords: automatic analyzer; fluorescence derivatization; highly polar carboxylic acid; liquid chromatography