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ABSTRACT: Microemulsion electrokinetic chromatography (MEEKC) is a mode of CE, which utilises microemulsion (ME) as the background electrolyte to achieve separation of a diverse range of analytes. MEs are composed of nanometre-sized oil droplets suspended in aqueous buffer which are stabilised by the presence of a surfactant and co-surfactant. These MEs are commonly referred to as oil-in-water MEs and their application in MEEKC has been extensively examined. This review details advances in the theory, methodoLogy and application of MEEKC during the period 2010-2012. Areas covered include online sample concentration, advances in chiral separations, use of coated capillaries, chemometric approaches and the use of novel additives to the microemulsion system. This review also provides the reader with an introduction to MEEKC and a presentation of recent applications.
Electrophoresis 10/2012; · 3.30 Impact Factor
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ABSTRACT: MEEKC is an electrodriven separation technique that utilises the unique properties of a microemulsion (ME) as a background electrolyte to achieve separation of a diverse range of solutes. MEs are composed of nanometre-sized oil droplets suspended in aqueous buffer, which is commonly referred to as oil-in-water ME. The droplets are stabilised by the presence of both a surfactant and co-surfactant. The use of water-in-oil MEs in MEEKC has also been investigated. This review details the advances in MEEKC-based separations from the period June 2008 – June 2010. Areas covered include online sample concentration, suppressed electroosmosis MEEKC, chiral separations, MEEKC-MS, MEEKC-ICP-MS and ME structure characterisation. The review also includes a fundamental introduction to MEEKC, along with a review of recent applications.
Electrophoresis 11/2010; 32(1):184 - 201. · 3.30 Impact Factor
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ABSTRACT: MEEKC is an electrodriven separation technique, which utilises the unique properties of a microemulsion (ME) as a background electrolyte to achieve separation of a diverse range of solutes. MEs are composed of nanometre-sized oil droplets suspended in aqueous buffer, which is commonly referred to as an oil-in-water ME. The droplets are stabilised by the presence of a surfactant and co-surfactant. The use of water-in-oil MEs in MEEKC has also been investigated. This review details the advances in MEEKC-based separations from the period 2008 to 2009. Areas covered include online sample concentration, suppressed electroosmosis MEEKC, chiral separation, MEEKC-MS, and structure-migration relationships. The review also includes a fundamental introduction to MEEKC, along with the presentation of recent applications.
Electrophoresis 02/2010; 31(5):755-67. · 3.30 Impact Factor
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ABSTRACT: MEEKC is an electrodriven separation technique. Oil-in-water microemulsions (MEs) and to a lesser extent water-in-oil MEs have been used in MEEKC as BGEs to achieve separation of a diverse range of solutes. The more common (oil-in-water) MEs are composed of nanometre-sized droplets of oil suspended in an aqueous buffer. Interfacial tension between the oil and aqueous phase is reduced close to zero by the presence of a surfactant and a co-surfactant. MEEKC is capable of providing fast and efficient separations for a wide range of acidic, basic and neutral, water-soluble and -insoluble compounds. This review details the advances in MEEKC-based separations from the period 2006 to 2008. Areas covered include online sample concentration, chiral separation, suppressed electroosmosis MEEKC, MEEKC-MS, and the use of MEEKC in predicting migration behaviour and solute characteristics. A fundamental introduction to MEEKC, along with the presentation and discussion of recent applications is also included.
Electrophoresis 01/2009; 30(1):65-82. · 3.30 Impact Factor
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ABSTRACT: Rapid MELC and MEEKC methods were developed for paracetamol suppository assay. MELC methods for paracetamol analysis and for
separation of paracetamol and its impurities were previously reported. In this study, further development of MEEKC methods
and a MELC method using anionic and cationic microemulsions gave excellent validation results for paracetamol content in suppositories.
SDS Microemulsion instability resulted in poor reproducibility for impurity separations using gradient elution. A novel isocratic
CTAB MELC method achieved reproducible separation of paracetamol and its impurities at 0.1% levels. MEEKC methods using SDS
and CTAB microemulsions resolved all of the impurities however detection at 0.1% levels was not possible. These methods gave
significant benefits in terms of reduced sample pre-treatment requirements. CTAB microemulsions had greater solubilising power
than their SDS equivalent and were more stable due to their longer alkyl chain length.
Chromatographia 06/2008; 68(1):49-56. · 1.20 Impact Factor
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ABSTRACT: This chapter describes the application of capillary electrophoresis (CE) to pharmaceutical analysis. The areas of pharmaceutical analysis covered are enantiomer separation, analysis of small molecules such as amino acids or drug counter-ions, pharmaceutical assay, related substances determinations, and physiochemical measurements such as log P and pKa of compounds. The different electrophoretic modes available and their advantages for pharmaceutical analysis are described. Recent applications of CE for each subject area are tabulated with electrolyte details. Information on electrolyte choice and method optimization to obtain optimal separations is included.
Methods in molecular biology (Clifton, N.J.) 02/2008; 384:205-45.
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09/2007: pages 115 - 135; , ISBN: 9780470871041
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ABSTRACT: A rapid and efficient oil-in-water microemulsion liquid chromatographic method has been optimised and validated for the analysis of paracetamol in a suppository formulation. Excellent linearity, accuracy, precision and assay results were obtained. Lengthy sample pre-treatment/extraction procedures were eliminated due to the solubilising power of the microemulsion and rapid analysis times were achieved. The method was optimised to achieve rapid analysis time and relatively high peak efficiencies. A standard microemulsion composition of 33 g SDS, 66 g butan-1-ol, 8 g n-octane in 1l of 0.05% TFA modified with acetonitrile has been shown to be suitable for the rapid analysis of paracetamol in highly hydrophobic preparations under isocratic conditions. Validated assay results and overall analysis time of the optimised method was compared to British Pharmacopoeia reference methods. Sample preparation and analysis times for the MELC analysis of paracetamol in a suppository were extremely rapid compared to the reference method and similar assay results were achieved. A gradient MELC method using the same microemulsion has been optimised for the resolution of paracetamol and five of its related substances in approximately 7 min.
Journal of Pharmaceutical and Biomedical Analysis 06/2007; 44(1):137-43. · 2.97 Impact Factor
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ABSTRACT: Microemulsion EKC (MEEKC) is an electrodriven separation technique. Separations are typically achieved using oil-in-water microemulsions, which are composed of nanometre-sized oil droplets suspended in an aqueous buffer. The droplets are stabilised by a surfactant and a cosurfactant. The novel use of water-in-oil microemulsions has also been investigated. This review summarises the advances in the development of MEEKC separations and also the different areas of application including determination of log P values, pharmaceutical applications, chiral analysis, natural products and bioanalytical separations and the use of new methods such as multiplexed MEEKC and high speed MEEKC. Recent applications (2004-2006) are tabulated for each area with microemulsion composition details.
Electrophoresis 02/2007; 28(1-2):193-207. · 3.30 Impact Factor
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ABSTRACT: This paper reviews the application of CE to the analysis of small-molecule pharmaceuticals. The areas of pharmaceutical analysis covered are enantiomer separation, the analysis of small molecules such as amino acids or drug counter-ions, pharmaceutical assay, determination of related substances and physicochemical measurements such as log P and pK(a) of compounds. The different electrophoretic modes available and their advantages for pharmaceutical analysis are described. Recent applications of CE for each subject area are tabulated with electrolyte details.
Electrophoresis 07/2006; 27(12):2263-82. · 3.30 Impact Factor
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ABSTRACT: Water-in-oil microemulsion electrokinetic chromatography has been applied to the separation of a range of acids, bases and neutrals and is especially suitable for very water-insoluble drug compounds. A number of operating parameters were evaluated. An optimised set of operating conditions allowed separation of a range of pharmaceutical formulations containing water-insoluble compounds. A number of novel applications for W/O microemulsions were developed and ability to quantify drug contents in tablets and a cream was shown with good precision, detector linearity and accuracy. Comparison of obtained data with those determined from a HPLC method showed acceptable agreement.
Journal of Pharmaceutical and Biomedical Analysis 05/2005; 37(5):877-84. · 2.97 Impact Factor
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ABSTRACT: Microemulsion electrokinetic chromatography (MEEKC) is an electrodriven separation technique. Separations are typically achieved using oil-in-water microemulsions, which are composed of nanometre-sized droplets of oil suspended in aqueous buffer. The oil droplets are coated in surfactant molecules and the system is stabilised by the addition of a short-chain alcohol cosurfactant. The novel use of water-in-oil microemulsions for MEEKC separations has also been investigated recently. This report summarises the different microemulsion types and compositions used to-date and their applications with a focus on recent papers (2002-2004). The effects of key operating variables (pH, surfactant, cosurfactant, oil phase, buffer, additives, temperature, organic modifier) and methodology techniques are described.
Electrophoresis 01/2005; 25(23-24):3970-80. · 3.30 Impact Factor
