Separation of catechins and methylxanthines in tea samples by capillary electrochromatography.
In this paper, the simultaneous separation of several polyphenols such as (+)-catechin, (-)-epicatechin, (-)-epigallocatechin, theophylline, caffeine in green and black teas by capillary electrochromatography (CEC) was developed. Several experimental parameters such as stationary phase type, mobile phase composition, buffer and pH, inner diameter of the columns, sample injection, were evaluated to obtain the complete separation of the analysed compounds. Baseline resolution of the studied polyphenols was achieved within 30 min by using a capillary column (id 100 microm) packed with bidentate C(18) particles for 24.5 cm and a mobile phase composed of 5 mM ammonium acetate buffer pH 4 with H(2)O/ACN (80:20, v/v). The applied voltage and the temperature were set at 30 kV and 20 degrees C. Precision, detection and quantification limits, linearity, and accuracy were investigated. A good linearity (R(2) > 0.9992) was achieved over a concentration working range of 2-100 microg/mL for all the analytes. LOD and LOQ were 1 and 2 microg/mL, respectively, for all studied compounds. The CEC method was applied to the analysis of those polyphenols in green and black tea samples after an extraction procedure. Good recovery data from accuracy studies ranged between 90% and 112% for all analytes.
Uysal
Ulku Dilek
UD
Institute of Chemical Methodologies, National Council of Research, Area della Ricerca di Roma 1, Monterotondo Scalo, Rome, Italy.
Aturki
Zeineb
Z
Raggi
Maria Augusta
MA
Fanali
Salvatore
S
D053801:Capillary Electrochromatography / Q000379:methods*; D002392:Catechin / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D016014:Linear Models; D015394:Molecular Structure; D013662:Tea / Q000737:chemistry*; D014970:Xanthines / Q000302:isolation & purification*
D013662:Tea; D014970:Xanthines; C008514:methylxanthine; D002392:Catechin