Factors affecting tocopherol contents in coffee brews: NP-HPLC/FLD, RP-UPLC-ESI/MSn and spectroscopic study
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Qualitative and quantitative determination of tocopherols in filtered and unfiltered coffee brews was investigated. The NP-HPLC/FLD and RP-UPLC-ESI/MSn techniques as well as fluorescence spectroscopy turned out to be very useful tools not only to estimate tocopherol contents, but also to detect contaminants in coffee brew tocopherol extracts. In all analysed coffee brew samples, only α- and β-T were detected. In Arabica coffee brews, the content of the β homologue was three to four times higher than that of the α homologue; however, in Robusta, they were almost identical. Unfiltered coffee brews contained about ten times more tocopherols, 3.02–5.26 and 3.39–16.52, than filtered brews, 0.4–0.71 and 1.26–1.77 μg/100 ml for α-T and β-T, respectively. The reduction in the size of ground coffee beans from 0.7 to 0.3 mm increases the concentration of tocopherols almost three times. Suspended coffee bean dust was the main source of tocopherols in coffee brews.
KeywordsCoffee brew Tocopherols Fluorescence Arabica and Robusta NP-HPLC UPLC-ESI/MSn
Normal phase high-performance liquid chromatograph/fluorescence detector
Reverse phase ultra-performance liquid chromatography electrospray ionization/mass spectrometry
This study was partially supported by a grant 508/82-4 from the Poznan University of Life Sciences, Poznan, Poland, and by a grant N312 1410 33 from the Polish Ministry of Science and Higher Education.
Conflict of interest
Compliance with Ethics Requirements
This article does not contain any studies with human or animal subjects.
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