title: Determination of phenylenediamine isomers in hair dyes by coal cinders micro-column extraction and MEKC.
abstract: A new micellar electrokinetic chromatography (MEKC) method using beta-cyclodextrins (β-CDs) and 1-butyl-3-methylimidazolium hexafluorophosphates (ionic liquids) as additives was successfully developed for determination of para-, meta-, and ortho-phenylenediamines isomers (p-P, m-P, and o-P) in hair dyes. To improve the sensitivity of the MEKC-UV, a simple and cheap flow injection (FI) technique using a micro-column packed with coal cinders (the by-products from combustion in a boiler) as solid-phase extractant was also investigated. In the presence of 20 mmol L(-1) phosphates at pH 5.5, addition of 12 mmol L(-1) ionic liquids and 8 mmol L(-1) β-CDs greatly improved the separation efficiency. The three analytes could be quantitatively adsorbed by coal cinders, and desorbed readily with 0.15 mL of 0.01 mol L(-1) NaOH. Under the optimum conditions, an enrichment factor (EF) of 33.3 was obtained, and determination limits of p-P, m-P, and o-P were 1.97 × 10(-7), 0.99 × 10(-7), and 0.61 × 10(-7) mol L(-1), respectively. The adsorption capacities of the coal cinders micro-column for p-P, m-P, and o-P were all 1.20 mg g(-1). The presented procedure was successfully applied to the determination of p-P, m-P, and o-P in hair dyes with satisfactory results.
authors.affiliation: Department of Chemistry and Environmental Engineering, Hubei Key Laboratory of Pollutant Analysis and Reuse Technique, Hubei Normal University, Huangshi, 435002, China. chemwuyiwei@tom.com
authors.forename: Yiwei
authors.initials: Y
authors.lastname: Wu
authors.forename: Feng
authors.initials: F
authors.lastname: Jiang
authors.forename: Lin
authors.initials: L
authors.lastname: Chen
authors.forename: Jing
authors.initials: J
authors.lastname: Zheng
authors.forename: Zhenli
authors.initials: Z
authors.lastname: Deng
authors.forename: Qing
authors.initials: Q
authors.lastname: Tao
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.forename: Lijuan
authors.initials: L
authors.lastname: Han
authors.forename: Xiaoshu
authors.initials: X
authors.lastname: Wei
authors.forename: Aimin
authors.initials: A
authors.lastname: Yu
authors.forename: Haili
authors.initials: H
authors.lastname: Zhang
mesh_terms: D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D003031:Coal; D006202:Hair Dyes / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007536:Isomerism; D010655:Phenylenediamines / Q000032:analysis* / Q000737:chemistry; D052616:Solid Phase Extraction / Q000379:methods*
chemical_list: D003031:Coal; D006202:Hair Dyes; D010655:Phenylenediamines