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.

Exploring versatile applications of cyclodextrins: an overview

“…Suitable method was developed. Wu et al (2011) CD also helps in altering the taste and removal of undesirable bitter tastes and odors of food products. Certain food products have a very bad smell but, on addition of CDs during their manufacturing, inclusion complexes are formed between CD and food components thereby improving the smell of the resultant product.…”

Determination of Three Phthalate Esters in Environmental Samples by Coal Cinder Extraction and Cyclodextrin Modified Micellar Electrokinetic Chromatography

“…The coal cinder of 130 -160 mesh size (obtained from the boiler house of Hubei Normal University) was immersed in 3.0 mol/L hydrogen chloride (HCl) and sodium hydroxide (NaOH), each for 24 h, filtered, washed with DDW until it became neutral and dried prior to storage for later use. The results of Brunauer-Emmett-Teller (BET) measurements and the curve of nitrogen desorption (32) showed that the specific surface area of the coal cinder was 50.3 m 2 /g 21 , and the pore size distribution (PSD) curve for the coal cinder was narrow (approximately 2-4 nm).…”

Micellar electrokinetic chromatography: A review of methodological and instrumental innovations focusing on practical aspects

“…Further study is still required to assess their real potential in MEKC. In one, Wu et al developed a new MEKC method using β‐CDs and 1‐butyl‐3‐methylimidazolium hexafluorophosphates (ionic liquids) as additives for the determination of phenylenediamine isomers in hair dyes.…”