Application of capillary electrophoresis to tea quality estimation

Horie, Hideki; Kohata, Katsunori

doi:10.1016/s0021-9673(97)01069-8

Cited by 95 publications

(64 citation statements)

References 7 publications

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“…Catechins are chemically unstable in an alkaline environment showing extensive peak tailing and distortion above pH 7.6 [23]. Therefore, the influence of the pH was studied in first instance using three buffer systems in the neutral and acidic region: 50 mM acetic-acetate at pH 5.0, 50 mM dihydrogenphosphate-hydrogen phosphate at pH 6.0 and 7.0, containing each buffer 100 mM SDS.…”

Section: Mekc Studies With Sdsmentioning

confidence: 99%

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Mixed micellar electrokinetic capillary chromatography separation of depolymerized grape procyanidins

et al. 2003

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Oligomeric procyanidins are potent antioxidant polyphenols of potential interest as disease-preventing agents. Their efficiency depends on the size and composition of their oligomeric structures. The mean degree of polymerization of these compounds is usually estimated by thiolysis with thiol-alpha-toluene followed by analysis using high-performance liquid chromatography (HPLC). We show the development of a mixed micellar electrokinetic chromatography (MEKC) method for the separation of the major components obtained after thiolysis with cysteamine (catechins and their cysteamine conjugates). MEKC studies using sodium dodecyl sulfate (SDS as pseudostationary phase led to long migration times, e.g., with 100 mM SDS, at pH 7, the solutes were separated in about 40 min), while the use of sodium cholate (SC) produced an elution window relatively short. Using a mixed micellar SC-SDS system (50 mM phosphate at pH 7 containing 40 mM SC and 10 mM SDS), it is possible to separate these compounds in less than 15 min. The proposed method is useful to separate the major components of the thiolysate in effluents from food processing (e.g., skins and seeds from grape and apple) considered as potential procyanidin sources.

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Section: Mekc Studies With Sdsmentioning

confidence: 99%

“…Several MEKC procedures have been developed for the separa- tion of catechins in different plants, mainly tea samples [21][22][23][24][25][26][27]. Cifuentes et al [28] described a method for the separation of three procyanidins dimers (B1, B2 and B3) and their monomers (Cat, Ec) using acidic MEKC buffers.…”

Section: Introductionmentioning

confidence: 99%

Mixed micellar electrokinetic capillary chromatography separation of depolymerized grape procyanidins

et al. 2003

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“…Additionally, analysis of theanine together with other compounds was reported by means of capillary electrophoresis (CE) and micellar electro-2 . Experimental kinetic capillary chromatography (MECC) using UV absorbance detection [12,13]. Since theanine is lack-2 .1.…”

Section: Introductionmentioning

confidence: 99%

Direct determination of free amino acids and sugars in green tea by anion-exchange chromatography with integrated pulsed amperometric detection

Ding

Mou

2002

Journal of Chromatography A

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Determination of amino acids and sugars in green tea by anion-exchange chromatography with integrated pulsed amperometric detection was developed. Amino acids and sugars were separated on an anion-exchange column at a flow-rate of 0.25 ml / min by using ternary gradient elution consisting of deionized water, 0.25 M sodium hydroxide, and 1.0 M sodium acetate. Under optimized conditions, theanine was separated from glutamine and three sugars (glucose, fructose, and sucrose) were eluted earlier than the neutral amino acids to avoid their interference with each other. RSDs of the peak area of analytes were lower than 4.6%. Detection limits for the analytes ranged from 0.12 to 4.9 pmol. The linearities for all analytes were two or three orders of magnitude with the correlation coefficients greater than 0.99. This method was applied to determination of amino acids and sugars in green tea with satisfactory results. 

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“…Catechins have been shown to display antioxidant activity, and are postulated to have antimutagenic and anticarcinogenic properties [36]. Concerning the analysis of chiral catechins by CZE, tea has been the most extensively studied [36][37][38], including extracts of green tea, oolong tea and black tea. Different leaf parts of a young shoot were also analysed with results showing that a wide variation exists among the components of the leaf parts.…”

Section: Catechinsmentioning

confidence: 99%

CE methods applied to the analysis of micronutrients in foods

2007

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This article reviews the applications of CE that are relevant to the analysis of small molecules in foods. CE has been applied to a wide range of important areas of food analysis and is rapidly being established as an alternative technique to chromatographic methods including HPLC and GC within analytical food and research laboratories. In recent years the analysis of food by CE has become more frequent and important and as such a variety of compounds have been separated and quantified. Although many other analytes have been detected by CE, this review will highlight areas relating primarily to the rather broad chemical classes of free amino acids, carbohydrates, organic acids, vitamins and a variety of antioxidants. In addition, information relating to the analyte, sample matrix, mode of CE employed, scope of the methodology and the detection and derivatization of the small molecules are considered and discussed.

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Application of capillary electrophoresis to tea quality estimation

Cited by 95 publications

References 7 publications

Mixed micellar electrokinetic capillary chromatography separation of depolymerized grape procyanidins

Mixed micellar electrokinetic capillary chromatography separation of depolymerized grape procyanidins

Direct determination of free amino acids and sugars in green tea by anion-exchange chromatography with integrated pulsed amperometric detection

CE methods applied to the analysis of micronutrients in foods

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