title: Analysis of sudan I, sudan II, sudan III, and sudan IV in food by HPLC with electrochemical detection: Comparison of glassy carbon electrode with carbon nanotube-ionic liquid gel modified electrode.
abstract: A method was developed for analyzing of sudan I, sudan II, sudan III, and sudan IV by high performance liquid chromatography coupled with an electrochemical detector. The electrochemical oxidation of each compound was investigated with a carbon nanotube-ionic liquid gel modified glassy carbon (MWNTs-IL-Gel/GC) electrode using cyclic voltammetry. The results were compared with those of glassy carbon electrodes. At the MWNTs-IL-Gel/GC electrode, highly reproducible, well-defined cyclic voltammograms for sudan oxidation were obtained. In the flow system, MWNTs-IL-Gel/GC exhibited highly reproducible and well-defined amperometric signals without peak tailing. In addition, the determination of sudan dyes by mean of isocratic reverse-phase HPLC, with amperometric detection at MWNTs-IL-Gel/GC and GC electrode, have been investigated. The chromatograms showed excellent separation. The detection limits ranged from 0.001 to 0.005ppm. The method was sensitive, selective and could be applicable for the assay of sudan dyes in soft drink samples.
authors.affiliation: Sensor Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand. Electronic address: corawon@chula.ac.th.
authors.forename: Orawon
authors.initials: O
authors.lastname: Chailapakul
authors.affiliation: Sensor Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
authors.forename: Wanida
authors.initials: W
authors.lastname: Wonsawat
authors.affiliation: Department of Chemistry, Faculty of Science, Srinakharinwirot University, Sukumvit 23 Road, Wattana, Bangkok 10110, Thailand.
authors.forename: Weena
authors.initials: W
authors.lastname: Siangproh
authors.affiliation: Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand.
authors.forename: Kate
authors.initials: K
authors.lastname: Grudpan
authors.affiliation: Institute of Analytical Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, PR China.
authors.forename: Yifang
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Institute of Analytical Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, PR China.
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Zhu
keywords: Carbon nanotube; Electrochemical detection; Food analysis; HPLC; Sudan I; Sudan II; Sudan III; Sudan IV; Sudan azo-dyes