title: Determination of imidazole derivatives by micellar electrokinetic chromatography combined with solid-phase microextraction using activated carbon-polymer monolith as adsorbent.
abstract: In this study, an effective method for the separation of imidazole derivatives 2-methylimidazole (2-MEI), 4- methylimidazole (4-MEI) and 2-acetyl-4-tetrahydroxybutylimidazole (THI) in caramel colors using cation-selective exhaustive injection and sweeping micellar electrokinetic chromatography (CSEI-sweeping-MEKC) was developed. The limits of detection (LOD) and quantitation (LOQ) for the CSEI-sweeping-MEKC method were in the range of 4.3-80μgL(-1) and 14-270μgL(-1), respectively. Meanwhile, a rapid fabrication activated carbon-polymer (AC-polymer) monolithic column as adsorbent for solid-phase microextraction (SPME) of imidazole colors was developed. Under the optimized SPME condition, the extraction recoveries for intra-day, inter-day and column-to-column were in the range of 84.5-95.1% (<6.3% RSDs), 85.6-96.1% (<4.9% RSDs), and 81.3-96.1% (<7.1% RSDs), respectively. The LODs and LOQs of AC-polymer monolithic column combined with CSEI-sweeping-MEKC method were in the range of 33.4-60.4μgL(-1) and 111.7-201.2μgL(-1), respectively. The use of AC-polymer as SPME adsorbent demonstrated the reduction of matrix effect in food samples such as soft drink and alcoholic beverage thereby benefiting successful determination of trace-level caramel colors residues using CSEI-sweeping-MEKC method. The developed AC-polymer monolithic column can be reused for more than 30 times without any significant loss in the extraction recovery for imidazole derivatives.
authors.affiliation: Department of Chemistry, Chung Yuan Christian University, 200 Chung Pei Road, Chung Li District, Taoyuan City 320, Taiwan.
authors.forename: Yung-Han
authors.initials: YH
authors.lastname: Shih
authors.affiliation: Department of Chemistry, Chung Yuan Christian University, 200 Chung Pei Road, Chung Li District, Taoyuan City 320, Taiwan.
authors.forename: Stephen
authors.initials: S
authors.lastname: Lirio
authors.affiliation: Department of Chemistry, Chung Yuan Christian University, 200 Chung Pei Road, Chung Li District, Taoyuan City 320, Taiwan.
authors.forename: Chih-Keng
authors.initials: CK
authors.lastname: Li
authors.affiliation: Department of Chemistry, Chung Yuan Christian University, 200 Chung Pei Road, Chung Li District, Taoyuan City 320, Taiwan.
authors.forename: Wan-Ling
authors.initials: WL
authors.lastname: Liu
authors.affiliation: Department of Chemistry, Chung Yuan Christian University, 200 Chung Pei Road, Chung Li District, Taoyuan City 320, Taiwan. Electronic address: hyhuang@cycu.edu.tw.
authors.forename: Hsi-Ya
authors.initials: HY
authors.lastname: Huang
mesh_terms: D002606:Charcoal / Q000737:chemistry*; D020374:Chromatography, Micellar Electrokinetic Capillary; D005504:Food Analysis / Q000379:methods*; D007093:Imidazoles / Q000032:analysis* / Q000737:chemistry; D057230:Limit of Detection; D011108:Polymers / Q000737:chemistry*; D052617:Solid Phase Microextraction
chemical_list: D007093:Imidazoles; D011108:Polymers; D002606:Charcoal
keywords: Activated carbon (AC); Caramel colors; Imidazole derivatives; Micellar electrokinetic chromatography (MEKC); Polymer monolith; Solid-phase microextraction (SPME)