Recent novel MEKC applications to analyze free amino acids in different biomatrices: 2009–2010

Viglio, Simona; Fumagalli, Marco; Ferrari, Fábio; Bardoni, Anna; Salvini, Roberta; Giuliano, Serena; Iadarola, Paolo

doi:10.1002/elps.201100336

Cited by 17 publications

(13 citation statements)

References 90 publications

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“…Such analyses poise an analytical challenge, where chiral CE is a valuable alternative, considering its high separation efficiency, very high resolving power and small sample and reagents consumption. In the past two years, chiral CE has been reviewed by some authors .…”

Section: Enantioselective Separationsmentioning

confidence: 99%

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Recent advances in amino acid analysis by capillary electromigration methods, 2011–2013

et al. 2013

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This article describes the most important research published on amino acid (AA) analysis using CE during the period from June 2011 to May 2013, and follows the format of the previous articles of Smith (Electrophoresis 1999, 20, 3078-3083), Prata et al. (Electrophoresis 2001, 22, 4129-4138), and Poinsot et al. (Electrophoresis 2003, 24, 4047-4062; Electrophoresis 2006, 27, 176-194; Electrophoresis 2008, 29, 207-223; Electrophoresis 2010, 31, 105-121; Electrophoresis 2012, 33, 14-35). We present new developments in AA analysis with CE, mainly describing the use of MS or LEDs for detection following conventional or enantiomeric separation developments. In addition, in an application part, we describe neurochemical or clinical studies, metabolomics for plant extracts and biological fluids, and finally works focused on AAs in food and agricultural applications.

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Section: Enantioselective Separationsmentioning

confidence: 99%

“…In this review, we will show that the use of CE/MS for AA determination in a metabolomic approach remains a dynamic topic. Other reviews reporting on CE separation techniques (i.e., enantomeric separations and MEKC) appeared at the end of time period .…”

Section: Introductionmentioning

confidence: 99%

Recent advances in amino acid analysis by capillary electromigration methods, 2011–2013

et al. 2013

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“…[1][2][3] Among the various CE modes, micellar electrokinetic chromatography (MEKC) using surfactants such as sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide has become a powerful separation technique for both neutral and ionic compounds in complicated mixtures containing a broad range of analytes. 4,5 The principle of MEKC is based on differential partitioning between the micellar and aqueous phases. A major disadvantage of CE is its low concentration sensitivity, which is due to the short optical path length for online UV detection and the low injection volumes of the sample solution.…”

Section: Introductionmentioning

confidence: 99%

“…These strategies include field amplified sample stacking, large volume sample stacking, transient isotachophoresis, dynamic pH junction, and sweeping. [4][5][6][7][8] Sweeping is an on-line concentration method for either charged or neutral analytes, whose effectiveness relies on how pseudostationary phase enters the sample solution zone and sweeps the analytes. 4,5 The alkyl esters of p-hydroxybenzoic acid (commonly known as parabens), including methyl (MP), ethyl (EP), propyl (PP), and butyl (BP) parabens, are some of the most widely used types of preservatives in foodstuffs, beverages, cosmetics, pharmaceuticals, and personal care products because of their broad antimicrobial spectrum, relatively low toxicity, good stability, non-volatility and efficiency over a wide pH range.…”

Section: Introductionmentioning

confidence: 99%

“…[4][5][6][7][8] Sweeping is an on-line concentration method for either charged or neutral analytes, whose effectiveness relies on how pseudostationary phase enters the sample solution zone and sweeps the analytes. 4,5 The alkyl esters of p-hydroxybenzoic acid (commonly known as parabens), including methyl (MP), ethyl (EP), propyl (PP), and butyl (BP) parabens, are some of the most widely used types of preservatives in foodstuffs, beverages, cosmetics, pharmaceuticals, and personal care products because of their broad antimicrobial spectrum, relatively low toxicity, good stability, non-volatility and efficiency over a wide pH range. [9][10][11] Their antimicrobial activity and octanol/water partition coefficient increase with the molecular weight and length of the alkyl side chain; 12 however, in practice, shorter esters are commonly employed because of their higher aqueous solubility.…”

Section: Introductionmentioning

confidence: 99%

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On‐line Concentration and Separation of Parabens by Micellar Electrokinetic Chromatography Using Polymer Solutions

Lee

et al. 2014

J Chinese Chemical Soc

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Simultaneous separation and quantification of seven parabens commonly used as preservatives in cosmetic products, by micellar electrokinetic chromatography with a stacking technique has been demonstrated. An effective on-line concentration strategy involving a combination of sweeping and the use of polymer solutions is a key feature of the proposed method, which successfully determined individual parabens. The analysis parameters such as injection time, pH and concentration of phosphate solution, and concentration of sodium dodecyl sulphate (SDS) and poly(ethylene oxide) (PEO) were examined. The optimum conditions were found to be as follows: a 15 mM phosphate solution (pH 9.5) containing 20 mM SDS for filling the capillary, and for the separation electrolytes, 0.100% PEO (8 MDa) added to the phosphate and SDS solution of the same composition as for the capillary. The entire analysis process was completed in 13 min and a 930-2200-fold enhancement factor was achieved. The LODs (S/N = 3) for this approach were in the range from 4.32 to 7.78 nM. The linear range for each paraben was between 50 nM and 5.0 mM (R 2 > 0.990). The optimized method was then successfully applied to the determination of parabens in commercial cosmetic products.

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Micellar Electrokinetic Chromatography

Pyell

2000

Encyclopedia of Analytical Chemistry

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Micellar electrokinetic chromatography (MEKC) is a highly efficient capillary‐format separation technique that is performed with the same experimental setup, which is used with capillary electrophoresis (CE). While the separation principle of CE is based on the differences in the effective electrophoretic mobility of the solutes to be separated (only charged species can be separated), MEKC separation is also based on the differences in the distribution constants between two phases migrating at a different velocity because of electrokinetic effects. In general, the second phase is introduced into the separation electrolyte/background electrolyte (BGE) by adding an ionic surfactant (anionic or cationic) in a concentration above the critical micellar concentration (CMC). Under these conditions, dynamic association colloids (micelles) are formed. These aggregates have an electrophoretic mobility and are able to incorporate solutes or interact strongly with species dissolved in the surrounding medium. MEKC extends the applicability of CE to neutral solutes. In addition, MEKC has been proven to be superior to CE in the separation of very complex mixtures of solutes with similar electrophoretic mobility because of the various parameters that are available for the manipulation of the separation selectivity. MEKC can be regarded as a separation technique with a similar scope to that of reversed‐phase high‐performance liquid chromatography (RPHPLC) and other modes of high‐performance liquid chromatography HPLC competing with these modes regarding the efficiency of the separation system, separation speed, cost, and tolerance to matrix constituents, as in MEKC, no stationary phase is present, which can be fouled by irreversible sorption of matrix constituents of the sample. Owing to the small injection volume (few nanoliters) and the small detection volume, which is necessary to avoid intolerable instrumental band broadening, there is a strong need for online focusing methods and sensitive miniaturized detection techniques.

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Recent novel MEKC applications to analyze free amino acids in different biomatrices: 2009–2010

Cited by 17 publications

References 90 publications

Recent advances in amino acid analysis by capillary electromigration methods, 2011–2013

Recent advances in amino acid analysis by capillary electromigration methods, 2011–2013

On‐line Concentration and Separation of Parabens by Micellar Electrokinetic Chromatography Using Polymer Solutions

Micellar Electrokinetic Chromatography

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