Liquid chromatography with multi-channel electrochemical detection for the determination of epigallocatechin gallate in rat plasma utilizing an automated blood sampling device

Long, Hong; Zhang, Yongxin; Cregor, Meloney; Tian, Feifei; Coury, Louis A.; Kissinger, Candice B.; Kissinger, Peter T.

doi:10.1016/s0378-4347(01)00365-6

Cited by 27 publications

(19 citation statements)

References 20 publications

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“…Sodium monochloroacetate (an organic salt) is often used as a buffer system in the mobile phase of liquidchromatographic separation. Kuo 22 and Long 24 et al indicated that the use of sodium monochloroacetate can improve the stability, resolution, and sensitivity of organic analytes. Sodium monochloroacetate was simultaneously used as an eluent buffer and extract accelerant in the present work.…”

Section: Ion Species and Strength Effectmentioning

confidence: 99%

Determination of Polycyclic Aromatic Hydrocarbons in Water by Solid-Phase Microextraction and Liquid Chromatography

Chen

2004

ANAL. SCI.

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Section: Ion Species and Strength Effectmentioning

confidence: 99%

Determination of Polycyclic Aromatic Hydrocarbons in Water by Solid-Phase Microextraction and Liquid Chromatography

Chen

2004

ANAL. SCI.

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“…[3] The most abundant catechins are (À)-epigallocatechin gallate (EGCG) and (À)-epigallocatechin (ECG) the structures of which are shown in Scheme 1, and are thought to be the major effective compounds. [6] Note also that important characteristics of green tea such as taste, nutritional values, palatability and pharmacological effects depend substantially on their polyphenol content [7,8].…”

Section: Introductionmentioning

confidence: 99%

Electroanalytical Sensing of Green Tea Anticarcinogenic Catechin Compounds: Epigallocatechin Gallate and Epigallocatechin

2006

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A novel electroanalytical methodology for the sensing of anticarcinogenic catechin compounds epigallocatechin gallate (EGCG) and epigallocatechin (EGC) is presented. The protocol is based on the electrochemical oxidation of aminophenol in aqueous solutions, where the quinoneimine oxidation product chemically reacts with the EGCG or EGC compounds resulting in consumption of quinoneimine and consequently results in a reduction in the magnitude of the quinoneimine reduction wave, which is found to provide an analytical signal from which to indirectly detect EGCG and/or EGC. The voltammetric response of 2,6-dichloro-p-aminophenol (AP) at an edge plane pyrolytic graphite electrode in a pH 10 buffer solution to additions of EGCG is examined and AP is shown to be effective for the above analytical procedure. Basal plane pyrolytic graphite electrodes are then modified with 4-amino-2,6-diphenylphenol (phenyl-AP) where it is demonstrated that determination can proceed using the immobilized phenyl-AP in the form of surface deposited microcrystals, obviating the need for dissolving the molecules within the solution phase. We demonstrate proof-of-concept that the analysis using the modified electrode provides the determination of the total amount of catechin compounds, which is examined in a green tea sample, providing an indirect sensing technique for the determination of catechins in natural extracts.

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“…Absorption regions at 210, 230, 254, and 370-280nm are used to determine catechins, with evidence showing that when determining five catechins with electrochemical detectors, the sensitivity is 1000 times compared to using a UV detector (Umegaki et al, 1996), while others have shown ECD to be 300 times more sensitive than UV detectors, particularly, for determining catechins (Kumamoto et al, 2000). Meanwhile, amperometric detectors register catechins at potentials of 400mV and 900mV, with maximum signal observed at 750-800 mV (Long et al, 2001). However, in some cases, it is recommended to use 500-600 mV in order to eliminate concurrent oxidation compounds (Umegaki et al, 1996).…”

Section: Methodsmentioning

confidence: 99%

Determination of the Chemical Composition of Tea by Chromatographic Methods: A Review

Yashin¹,

Nemzer²,

Combet³

et al. 2015

JFR

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Despite the fact that mankind has been drinking tea for more than 5000 years, its chemical composition has been studied only in recent decades. These studies are primarily carried out using chromatographic methods. This review summarizes the latest information regarding the chemical composition of different tea grades by different chromatographic methods, which has not previously been reviewed in the same scope. Over the last 40 years, the qualitative and quantitative analyses of high volatile compounds were determined by GC and GC/MS. The main components responsible for aroma of green and black tea were revealed, and the low volatile compounds basically were determined by HPLC and LC/MS methods. Most studies focusing on the determination of catechins and caffeine in various teas (green, oolong, black and pu-erh) involved HPLC analysis.Knowledge of tea chemical composition helps in assessing its quality on the one hand, and helps to monitor and manage its growing, processing, and storage conditions on the other. In particular, this knowledge has enabled to establish the relationships between the chemical composition of tea and its properties by identifying the tea constituents which determine its aroma and taste. Therefore, assessment of tea quality does not only rely on subjective organoleptic evaluation, but also on objective physical and chemical methods, with extra determination of tea components most beneficial to human health. With this knowledge, the nutritional value of tea may be increased, and tea quality improved by providing via optimization of the growing, processing, and storage conditions.

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Liquid chromatography with multi-channel electrochemical detection for the determination of epigallocatechin gallate in rat plasma utilizing an automated blood sampling device

Cited by 27 publications

References 20 publications

Determination of Polycyclic Aromatic Hydrocarbons in Water by Solid-Phase Microextraction and Liquid Chromatography

Determination of Polycyclic Aromatic Hydrocarbons in Water by Solid-Phase Microextraction and Liquid Chromatography

Electroanalytical Sensing of Green Tea Anticarcinogenic Catechin Compounds: Epigallocatechin Gallate and Epigallocatechin

Determination of the Chemical Composition of Tea by Chromatographic Methods: A Review

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