Sample stacking for determination of aromatic acid impurities by microemulsion electrokinetic chromatography

Huang, Hsi‐Ya; Lin, Yu‐Ru; Hsieh, Shih-Huan

doi:10.1016/j.aca.2008.10.047

Cited by 19 publications

(15 citation statements)

References 20 publications

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“…They fall into two main categories: oil-in-water (O/W) microemulsion, where hydrophobic droplets of oil are dispersed in an aqueous buffer with the help of the surfactant and co-surfactant, and waterin-oil microemulsion when the water is dispersed homogenously in the oil phase. As a result of these properties, O/W MEEKC has been successfully used as pseudostationary phase (PSP) in CE for a variety of applications, including chiral separation [2,3], prediction of solute characteristics [4,5], bioanalysis [6,7], food and pharmaceutical analysis [8][9][10], sample preconcentration methods [11][12][13][14]. Specifically, water-in-oil microemulsion has been emerging as an alternative CE buffer [9,15,16] and has shown differential ability to separate neutral and acidic compounds compared with O/W MEEKC.…”

Section: Introductionmentioning

confidence: 99%

The use of novel ionic liquid‐in‐water microemulsion without the addition of organic solvents in a capillary electrophoretic system

Cao

Cheng

2010

Electrophoresis

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In this work, a new ionic liquid-in-water (IL/W) microemulsion without requiring toxic organic solvents was investigated as a pseudostationary phase (PSP) in CE. As observed during the IL/W microemulsion system, a fast and an efficient separation of eight phenolic acids was achieved using 1-butyl-3-methylimidazolivmhexa fluorophosphate (bmimPF(6)) as oil drops, Tween 20 as the surfactant, and borate as the BGE. The effects of oil phase, surfactant, buffer and pH on the separation were explored in detail to evaluate the novel PSP. In contrast, the detection efficiency of these same analytes was markedly decreased using oil-in-water (O/W) MEEKC. We have also validated the practicality of the IL/W microemulsion method by quantitative determination of acidic compounds in pharmaceutical injection. The results obtained indicated that an additional association between the IL cations and analytes tested seemed to play a prominent role in the separation mechanism exhibited by this novel PSP compared with the conventional O/W MEEKC.

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Section: Introductionmentioning

confidence: 99%

The use of novel ionic liquid‐in‐water microemulsion without the addition of organic solvents in a capillary electrophoretic system

Cao

Cheng

2010

Electrophoresis

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“…When optimising the online concentration of another set of isoquinoline alkaloids Yu et al [31] found the introduction of a water plug resulted in improved absorbance and higher reproducibility. When stacking aromatic acid impurities [32] the presence of a water or acid plug did not result in a significant sensitivity enhancement; however, the presence of a water and/or acid increased the peak height reproducibility between runs. During ASEI the presence of an acid plug can prevent the sample analytes from partitioning with the ME droplets before sample concentration occurs [18].…”

Section: Effect Of Water and Acid/basic Plugs On Online Sample Concenmentioning

confidence: 74%

“…In the latest study [32] the aromatic acids under investigation had between 1 and 3 carboxyl groups. The use of a matrix buffer of pH 8 resulted in the aromatic acids with two or three carboxyl groups becoming divalent or trivalent anions.…”

Section: Online Sample Concentration and Analyte Functional Groupmentioning

confidence: 99%

“…Huang et al [32] assessed the online sample concentration for a range of aromatic acids to investigate a correlation between analyte functional group and sensitivity enhancement. It had previously been noted that the CSEI concentration of tobacco alkaloids [20] had been modest (10-540-fold) in comparison to the ASEI concentration of phenolic acid compounds (96 000-238 000) [18].…”

Section: Online Sample Concentration and Analyte Functional Groupmentioning

confidence: 99%

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Advances in the theory and application of MEEKC

et al. 2010

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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.

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“…Only some of them or similar to them have been described. [11][12][13][14][15][16][17][18][19][20][21] In this investigation the several parameters that influence the separation were investigated including pH, concentration of buffer and applied voltage. However, it is generally tedious procedure to search for the optimal conditions.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous Separation and Determination of Benzoic Acid Compounds in the Plant Medicine by High Performance Capillary Electrophoresis

Gao

Wang

et al. 2010

J Chinese Chemical Soc

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A simple and inexpensive high performance capillary electrophoresis (HPCE) was applied to separate five benzoic acid compounds simultaneously. The investigation was carried out by micellar electrokinetic capillary chromatography (MECC). To avoid a time-consuming and tedious procedure, orthogonal experimental design OA 9 (3 4 ) for separation experiments was applied to find the optimal conditions in terms of the resolution and analytical time. The best conditions for separation were obtained using a 20 mM borax and 30 mM sodium dodecyl sulfate (SDS) buffer (pH 9.8) containing 2 mM b-CD and 4% methanol (v/v). Online UV detection was performed at 250 nm. A voltage of 16 kV was applied and the temperature was controlled at 25°C. Injection was performed for 5 s. The method was validated for the quantification of benzoic acid, salicylic acid and ortho-aminobenzoic acid in Radix Isatidis, a traditional plant medicine with removal of endotoxin. The separation and determination were satisfactory and quick.

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Sample stacking for determination of aromatic acid impurities by microemulsion electrokinetic chromatography

Cited by 19 publications

References 20 publications

The use of novel ionic liquid‐in‐water microemulsion without the addition of organic solvents in a capillary electrophoretic system

The use of novel ionic liquid‐in‐water microemulsion without the addition of organic solvents in a capillary electrophoretic system

Advances in the theory and application of MEEKC

Simultaneous Separation and Determination of Benzoic Acid Compounds in the Plant Medicine by High Performance Capillary Electrophoresis

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