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.
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机译：成功开发了一种新的胶束电动色谱（MEKC）方法，该方法使用β-环糊精（β-CD）和1-丁基-3-甲基咪唑六氟磷酸盐（离子液体）作为添加剂，用于测定对，间和邻苯二胺类异构体（pP，mP和oP）在染发剂中。为了提高MEKC-UV的灵敏度，还研究了一种简单而廉价的流动注射（FI）技术，该技术使用装有煤渣（锅炉中燃烧副产物）的微柱作为固相萃取剂。在pH 5.5下存在20 mmol L -1 磷酸盐的情况下，添加12 mmol L -1 离子液体和8 mmol L -1 β-CDs大大提高了分离效率。煤渣可以定量地吸附这三种分析物，并用0.15 mL的0.01 mol L -1 NaOH容易地解吸。在最佳条件下，获得的富集因子（EF）为33.3，pP，mP和oP的测定限分别为1.97×10 -7 ，0.99×10 −7 和0.61×10 −7 mol L -1 。煤渣微柱对p-P，m-P和o-P的吸附容量均为1.20 mg g -1 。所提出的方法已成功用于染发剂中p-P，m-P和o-P的测定，结果令人满意。
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