2014Journal article
Roman Dück
In this work, several types of column switching were used for a number of analytical problems in liquid chromatography. Thus, comprehensive two-dimensional liquid chromatography was used for the study of tea. This developed into a semi-quantitative comparison of catechins in matcha and sencha tea.This revealed that about twice as much catechins is absorbed in the consumption of matcha tea as with sencha tea. To evaluate the best combination of columns in the LC x LC, a vector based mathematical model was developed. This calculation makes it possible to determine the effective area in a two-dimensional chromatogram, independently of the complexity of the distribution of the chromatogram spots. With this method, the best combination of columns for the analysis of Radix Angelicae sinensis was determined on the basis of the effective area, the peak capacity and the orthogonality. These results do not correlate with the results of the Neue-test. The best column selection is determined not only by the selectivity of the phases but also by the properties of the analyte in the complex sample. Thus, the optimal combination of columns to assess the separation efficiency - directly from the two-dimensional chromatogram - is of great importance. The separation efficiency of on-line LC x LC was compared with off-line LC x LC, with the analysis of Radix Angelicae sinensis as an example. This showed, as was to be expected, that the off-line LCxLC method had a higher peak capacity (2683) than on-line LC x LC (661). However, this was accompanied by a significant increase in analysis time, from 5 to 28 hours. No significant difference was found in the orthogonality and the consumption of solvents. The great advantage of the online method is the larger number of substances detected,…
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Study type
Chemical / analytical
Measuring what is in matcha, or how to detect it.
Assigned automatically from the title, abstract and subject terms.
Topics
Matcha is a main subject here (named in the keywords).
Roman Dück. (2014). Einsatz der komprehensiven zweidimensionalen Flüssigchromatographie zur Analyse von Naturstoffen und die Entwicklung der Recycling Chromatographie zur Trennung chiraler Verbindungen.
Japanese matcha is a type of powdered green tea, grown in a traditional way. Shading of the plants during the growth period enhances the processes of synthesis and accumulation of biologically active compounds, including theanine,…
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Randomized controlled trialAntioxidants and polyphenolsL-theanine and caffeineProcessing, milling and qualityCited 114×