Article ID Journal Published Year Pages File Type
1242138 Talanta 2016 7 Pages PDF
Abstract

•A CD-MEKC method has been used for the analysis of 92 green tea samples.•Catechins and methylxanthines were used as indicators of the geographical origin.•Pattern recognition techniques were applied with satisfactory results.

Catechins and methylxanthines were determined in 92 green tea (GT) samples originating from Japan and China by using micellar electrokinetic chromatography with the addition of (2-hydroxypropyl)-β-cyclodextrin. GT samples showed high concentrations of (−)-epigallocatechin gallate and caffeine, with (−)-epigallocatechin, (−)-epicatechin gallate and (−)-epicatechin in relevant content and (+)-catechin, (−)-catechin and theobromine in much lower amounts. The amount of all the considered compounds was higher for Chinese GTs, with the exception of (−)-epicatechin gallate. Pattern recognition methods were applied to discriminate GTs according to geographical origin, which is an important factor to determine quality and reputation of a commercial tea product. Data analysis was performed by principal component analysis and hierarchical cluster analysis as exploratory techniques. Linear discriminant analysis and quadratic discriminant analysis were utilized as discrimination techniques, obtaining a very good rate of correct classification and prediction.

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Related Topics
Physical Sciences and Engineering Chemistry Analytical Chemistry
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